Airsoftjunkiez got this Modification guide to easily install P90 HPA kit into your Krytac P90. The Airsoftjunkiez HPA Krytac P90 Hydra kit is an easy-to-install upgrade that transforms your Krytac P90 into a high-performance HPA-powered airsoft rifle. The kit includes a Wolverine Airsoft Hydra Engine designed specifically for the P90, a custom 3D-printed chassis that supports multi-trigger functionality, and a premium Wolverine FCU.