REV Airsoft takes a look at the Challenger GBB Pistol from ICS Airsoft if it is better than the Tokyo Marui's best selling Hi-Capa series. The ICS Hi-Capa Challenger Green Gas Pistol is a well-built airsoft gun with a realistic blowback function for a solid feel. It features a durable metal slide and high-quality polymer body, and is powered by standard green gas or propane. It also includes a threaded adapter for attaching tracer units or other accessories.