The Superlative Arms patented Bleed Off Mode gas piston system for the AR-15 platform enhances gas flow management by releasing excess gas out the front of the block, rather than restricting it like traditional adjustable blocks. Gas adjustment (patented) - features 30 fixed positions located at the front of the block Bleed-off port (patented) - located at the front of the block, designed to vent forward, directing emissions away from the operator 3/4 inches x 1 inches clamp-on QPQ melonite 416 stainless steel piston gas block Right hand, full-automatic AR-15 bolt carrier, dark DLC 8620 steel Mid-length gas system/operating rod length