The Icarus Click Adjustable Gas Block FM Product's Icarus Click Adjustable Gas Block makes for solid and quick gas adjustments on your AR-15. The .750 gas block is easily tuned with a side adjust mechanism, that provides tactile feedback to the user. User has access to 24 different adjustment settings. The nitride finish is extremely durable. The gas block installs via standard AR-15 set screws on the bottom (included). Mfg: Foxtrot Mike Products