Product Description:
<br />
<br />1.Inside Dia: 35mm (1.35 inch)
<br />2.With steel nut(approx 1 inch) 
<br />3.Light weight in precision
<br />4.Easy and quick installation
<br />5.Universal keymod format
<br />6.High quality aluminum alloy in durable mil-spec style black matte finish
<br />7.Weight(+.750 Steel Gas Port) : 490g/556g/582g/635g/737g/780g/788g
<br />8.Overall Length: 7/9/10/12/13.5/15/16inch
<br />9.With tools, 2 pcs detachable picatinny
<br />10.Lower rail style with CNC procedure