Airsoft HPA Engine Parts & Seals

Maxx Models

Maxx CNC Aluminum Hopup Chamber MXW (for MTW Engine )

Low in stock

Maxx Models

MAXX CNC Aluminum Hopup Chamber MGW for GBB bucking (for MTW M4)

In stock

MAXX CNC Aluminium Advanced Feed Tube V (for MTW )

Maxx Models

MAXX CNC Aluminium Advanced Feed Tube V3 (for MTW 308)

Low in stock

PolarStar

PolarStar Kythera SA Complete O-Ring Set

In stock

PolarStar

PolarStar O-Ring Set F2

In stock

PolarStar

PolarStar Complete O-Ring and Screw Set (JACK - MP7 Excluded)

In stock

PolarStar

PolarStar JACK/F2 BV309A Bullet Valve 200PSI

In stock

PolarStar

PolarStar Kythera SA Disconnector

Low in stock

PolarStar

PolarStar Kythera SA Main Sear

Low in stock

PolarStar

PolarStar Kythera Trigger Link V2/V3

Low in stock

PolarStar

PolarStar F2 Nozzle

Please find the accurate measurement for your specific airsoft replica before purchasing. Consult the chart below to find which #number you need. From PolarStar: 'For cylinder conversion systems we assign numbers to the nozzles instead of using the rifle model. This is because the nozzle length can vary between the same gun model when made by different manufacturers. This can be from the manufacturer designing the rifle differently, or from the thickness of the gearbox shell affecting how far from the hop-up chamber the cylinder sits. Therefore one nozzle length may work in different rifle models but not necessarily work in the same model from a different manufacture. For example, a standard MP5 could require any of 4 different nozzle lengths depending on the manufacturer. For this reason we produce numerous different nozzle lengths to provide compatibility for a wide range of replicas. Below we are listing the make and model of the replicas which the nozzle length is most commonly used with but it may be compatible with more models. For a list of replicas which we have measured and calculated the compatible nozzle length, please visit our Help Center. Once you determine what number nozzle your replica requires, that number is universal across all engines that use the numbered nozzle system (excluding some model specific Kythera systems). So, if you determine your replica takes a #11 nozzle, then you will need to install the #11 nozzle for whichever system you are converting your replica with. If your gun is not listed in the compatibility database in our Help Center, a recommended nozzle length may calculated by measuring your original gearbox and nozzle. Using a set of calipers and following the diagram below, measure these specific areas of the gearbox and input them into the following formula. Please note that measurements need to be in thousands of an inch (0.001").'

F2 Centerline Nozzles: TIP = F + B - (A/2) + .2925 'A more precise measurement (which accounts for the hop-up and bucking in use) may be obtained by installing a nozzle into the system which is slightly too long for the replica and measuring the nozzle setback when placed into the hop-up. The measured tip length should be within +/- 0.010" of an exiting nozzle to be compatible. If the tip length you measure does not match up to a production nozzle within +/- 0.010" then a nozzle is not currently made for that rifle. However, please contact us with your measurements as custom nozzles can be special ordered.'

Num	Most Commonly Used With	Tip (Inches)
1	TM M4/M16, A&K PKM, TM MP5 A/SD, ICS MP5 A/SD, G&G KAC SR-25E2	1.205
2	CYMA AK, CYMA MP5 A/SD, G&G UMP	1.242
3	CA M249/MK46, A&K M249/MK46	1.19
4	G&G GR-25	1.8305
5	A&K SR-25, JG SR-25, ICS SIG 550/551/552	1.3435
6	KA FAL, TM MP5K, A&K M240	1.2745
7	PTS MASADA, CA SCAR-L	1.514
8	VFC SCAR-H	1.8875
9	EF/S&T TAR-21 COMP	1.2565
10	EF ARX160 ELITE	1.866
11	CA KAC LMG, VFC MP5 A/SD	1.127
12	LCT AK-47/74/M, LCT VSS/AS VAL	1.2155
13	A&K MASADA/ACR	1.7265
14	KA CZ 805 BREN, CG M249 FEATHERWEIGHT, A&K M60	1.769
15	EF/ARES G36KV/CV, JG G36	1.434
16	EF/S&T G36C	1.421
17	CA AUG	1.384
18	G&G MP5 A/SD	1.175
19	VFC/ECHO1 XCR	1.6065
20	CA G36, CYMA SR-25	1.406
21	Elite Force/CYMA MP5K, CA SA58	1.303

In stock

PolarStar

PolarStar Kythera SA Nozzles

Please find the accurate measurement for your specific airsoft replica before purchasing. Consult the chart below to find which #number you need.

From PolarStar: 'For cylinder conversion systems we assign numbers to the nozzles instead of using the rifle model. This is because the nozzle length can vary between the same gun model when made by different manufacturers. This can be from the manufacturer designing the rifle differently, or from the thickness of the gearbox shell affecting how far from the hop-up chamber the cylinder sits. Therefore one nozzle length may work in different rifle models but not necessarily work in the same model from a different manufacture. For example, a standard MP5 could require any of 4 different nozzle lengths depending on the manufacturer. For this reason we produce numerous different nozzle lengths to provide compatibility for a wide range of replicas. Below we are listing the make and model of the replicas which the nozzle length is most commonly used with but it may be compatible with more models. For a list of replicas which we have measured and calculated the compatible nozzle length, please visit our Help Center. Once you determine what number nozzle your replica requires, that number is universal across all engines* that use the numbered nozzle system. So, if you determine your replica takes a #11 JACK nozzle, then it will also take a #11 Kythera or F2 nozzle if you ever put a different system into it. *NOTE: The Kythera models which are made for a specific replica (e.g. A&K/JG SR-25) with a non-standard length cylinder will use a specific nozzle with a "K" prefix. Since they use a non-standard cylinder, the universal nozzle numbering system cannot be used for these models. However, the design and profile of the "K" nozzles are the same as the standard numbered nozzles and are cross compatible between standard and non-standard cylinders. Additionally, all nozzles are marked with their number with the exception of the #1 nozzle. These are produced in far greater quantities than all of the other nozzles so they are left unmarked to reduce production time.'

Num	Most Commonly Used With	Tip (Inches)
1 (Unmarked)	TM M4/M16, TM MP5 A/SD, ICS MP5 A/SD, G&G KAC SR-25E2	0.841
2	CYMA AK, CYMA MP5 A/SD, G&G UMP	0.882
4	G&G GR-25	1.466
5	ICS SIG 550/551/552	0.979
6	KA FAL, TM MP5K, A&K M240	0.910
7	PTS Masada, CA SCAR-L	1.150
8	VFC SCAR-H	1.523
9	E&L AK, S&T TAVOR	0.892
11	CA KAC LMG, VFC MP5 A/SD	0.763
12	LCT AK-47/74/M, LCT VSS/AS VAL	0.851
13	A&K MASADA/ACR, CYMA SR-25 (V2.5 Kythera SA)	1.362
14	KA CZ 805 BREN	1.405
15	JG G36	1.070
17	CA AUG	1.020
18	G&G MP5 (Blowback)	0.811
20	CA G36K	1.042
21	Elite Force/CYMA MP5K, CA SA58	0.938
K1	A&K/JG SR-25 (V2.5 Kythera SA)	1.314

In stock

PolarStar

PolarStar Jack Nozzles

Please find the accurate measurement for your specific airsoft replica before purchasing. Consult the chart below to find which #number you need.

From PolarStar: 'For cylinder conversion systems we assign numbers to the nozzles instead of using the rifle model. This is because the nozzle length can vary between the same gun model when made by different manufacturers. This can be from the manufacturer designing the rifle differently, or from the thickness of the gearbox shell affecting how far from the hop-up chamber the cylinder sits. Therefore one nozzle length may work in different rifle models but not necessarily work in the same model from a different manufacture. For example, a standard MP5 could require any of 4 different nozzle lengths depending on the manufacturer. For this reason we produce numerous different nozzle lengths to provide compatibility for a wide range of replicas. Below we are listing the make and model of the replicas which the nozzle length is most commonly used with but it may be compatible with more models. For a list of replicas which we have measured and calculated the compatible nozzle length, please visit our Help Center. Once you determine what number nozzle your replica requires, that number is universal across all engines that use the numbered nozzle system (excluding some model specific Kythera systems). So, if you determine your replica takes a #11 nozzle, then you will need to install the #11 nozzle for whichever system you are converting your replica with. If your gun is not listed in the compatibility database in our Help Center, a recommended nozzle length may calculated by measuring your original gearbox and nozzle. Using a set of calipers and following the diagram below, measure these specific areas of the gearbox and input them into the following formula. Please note that measurements need to be in thousands of an inch (0.001").'

JACK Centerline Nozzles: TIP = F + B - (A/2) - .0875

'A more precise measurement (which accounts for the hop-up and bucking in use) may be obtained by installing a nozzle into the system which is slightly too long for the replica and measuring the nozzle setback when placed into the hop-up.

The measured tip length should be within +/- 0.010" of an exiting nozzle to be compatible. If the tip length you measure does not match up to a production nozzle within +/- 0.010" then a nozzle is not currently made for that rifle. However, please contact us with your measurements as custom nozzles can be special ordered.'

Num	Most Commonly Used With	Tip (Inches)	OAL (Inches)
1	TM M4/M16, A&K PKM, TM MP5 A/SD, ICS MP5 A/SD, G&G KAC SR-25E2	0.8245	1.677
2	CYMA AK, CYMA MP5 A/SD, G&G UMP	0.8625	1.715
3	CA M249/MK46, A&K M249/MK46	0.8095	1.662
4	G&G GR-25	1.4505	2.303
5	A&K SR-25, JG SR-25, ICS SIG 550/551/552	0.9635	1.816
6	KA FAL, TM MP5K, A&K M240	0.8945	1.747
7	PTS MASADA, CA SCAR-L	1.1345	1.987
8	VFC SCAR-H	1.5075	2.36
9	EF/S&T TAR-21 COMP	0.8765	1.729
10	EF ARX160 ELITE	1.4865	2.339
11	CA KAC LMG, VFC MP5 A/SD	0.7475	1.6
12	LCT AK-47/74/M, LCT VSS/AS VAL	0.8355	1.688
13	A&K MASADA/ACR	1.3465	2.199
14	KA CZ 805 BREN, CG M249 FEATHERWEIGHT, A&K M60	1.3895	2.242
15	EF/ARES G36KV/CV, JG G36	1.0545	1.907
16	EF/S&T G36C	1.0415	1.894
17	CA AUG	1.0045	1.857
18	G&G MP5 A/SD	0.795	1.647
19	VFC/ECHO1 XCR	1.227	2.079
20	CA G36, CYMA SR-25	1.026	1.8785
21	Elite Force/CYMA MP5K, CA SA58	0.923	1.771

In stock

PolarStar

PolarStar "Hop Up Thing" V2 Rotary Hop unit for M4/M16

In stock

maxx model hop up chamber me standard m aeg bucking .jpg

MAXX Model

MAXX Model CNC Aluminium Hop Up Chamber 2026 (M4 / MTW)

In stock

maxx model threaded hpa front housing polarstar f .jpg

MAXX Model

MAXX Model CNC Aluminium Threaded HPA Front Housing 2026

In stock

maxx model titanium nozzle wolverine inferno gen mtw .jpg

MAXX Model

MAXX Model CNC Titanium Enhanced Nozzle for Wolverine Inferno 2026

Low in stock

Maxx Models

Maxx CNC Aluminum Hopup Chamber M4W for MTW

Out of stock

Maxx Models

MAXX CNC Aluminium Advanced Feed Tube V3 (for MTW M4)

Out of stock

Includes
	1 x CNC Aluminum Hopup Chamber M4W unit
	2 x CNC Acrylic Side Cover
	2 x CNC Brass 2.6mm Side Wing
	1 x CNC Steel Pivot Pin
	1 x CNC Aluminum Hopup Lever
	1 x CNC Aluminum Soft Round Nub
	1 x CNC Aluminum Soft Flat Nub (4mm)
	1 x CNC Aluminum Hard Concave Nub (4mm)
	3 x Steel Nub Spring
	1 x CNC Steel Spring Guide
	1 x Steel Upper Compression Spring
	1 x Steel Center Compression Spring
	1 x CNC Delrin Locking C-Clip
	1 x CNC Brass Barrel Spacer
	1 x Brass Barrel Spacer Holder Oring
	1 x CNC Aluminum Rotary Dial Knob
	1 x CNC Aluminum Inlet Adaptor (OD11mm)

Airsoft HPA Engine Parts & Seals

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Airsoft HPA Engine Parts & Seals

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