A.R.M.S.has brought their folding front sight into production. Earlier this was announced at SHOT 08, and A.R.M.S.has now reached production status. The Folding Front Sight functions as both a sight, and as the gas block, and when raised is similar in appearance to the standard AR15/ M16 front sight. This units can be used as a gas block replacement, or as a front sight in mounted in front of an extended rail.

http://www.armsmounts.com/