Video from Kaslab Airsoft showing you how to install the Umbrella R-Hop in the Wolverine Airsoft MTW HPA Rifle... "The Umbrella R-Hop System increases backspin on your BB, giving it a longer stable flightpath. Accuracy Ability to lift heavier BBs (0.4g+ with sufficient FPS). Precision Consitency from shot to shot with superior air seal. We suggest the compression system package for perfect airseal."