PolarStar JACK O-Ring & Screw Set – HPA Maintenance Kit

Keep your PolarStar JACK HPA engine running smoothly with this complete o-ring and screw replacement set. Over time, seals wear down and lose their grip – leading to air leaks, inconsistent velocity, and poor efficiency. This kit restores those critical seals in one go.

What’s Included

• 1× M1.5 × 6.5 (Buna 70) – front outside nozzle seal
• 2× M1.5 × 9.5 (Buna 70) – rear outside nozzle seals
• 1× M1.5 × 19.5 (Buna 70) – front cylinder thread relief seal
• 1× M1.0 × 18.5 (Buna 70) – captured between front cylinder and donut
• 3× M1.0 × 5.0 (Buna 70) – two on nozzle stem, one inside nozzle
• Plug screw – for secure reassembly

Why O-Ring Maintenance Matters

HPA systems rely entirely on air-tight seals to function. Worn or degraded o-rings allow air to escape before it reaches the cylinder, reducing pressure consistency and accuracy. Buna 70 rubber withstands repeated compression cycles, but periodic replacement ensures peak performance and reliability during skirmishes and milsim events.

Compatibility & Upgrades

This set fits all PolarStar JACK versions – including CQB, Tactical, and Compact – with the exception of the PM7 variant. Always verify your gearbox version before ordering. Pair with a silicone-based HPA lubricant for optimal longevity.

UK Legal & Site Notes

O-ring and screw sets are standard maintenance items and carry no legal restrictions. Most UK airsoft sites permit on-site HPA system checks and minor maintenance during dead times. Always inform your site chronograph operator before reinstalling your engine.

Order your PolarStar JACK o-ring set today and keep your HPA engine in top condition. Fast UK delivery available.