The Lightning Banjo by S2 Airsoft Designs is an upgrade part for Fusion Engines that dramatically improves air efficiency by improving poppet movement speed. Efficiency gains vary between 90% and 25% depending on setup and no pressure or FCU changes are needed for most setups. The Lightning Banjo works with stock and low flow poppets, shims, and all nozzles and works at 30-120psi. (Note: For long barrels and some gold poppet setups, dP adjustment may need increased to ensure the barrel isn’t under volumed, but despite the increased dP setting, efficiency still improves) The Lightning Banjo works the V2 fusion engine (V2 Gen 1 / Gen 2 requires modification to fit due to the full auto selector bar and switch location) Installation is easy. Stop worrying about how many shots you can shoot in game, install this and focus on the game. This is especially helpful for airstock setups and SAW gunners who need max efficiency!