Polar Star JACK HPA Conversion Kit for M4/M16 V2 Gearboxes

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  • $315.00
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The Polar Star JACK HPA Conversion Kit for M4/M16 V2 Gearboxes is the product you didn't think you need, but once you have it, something you won't want to live without.

Inventory Last Updated: Jul 22, 2026