SPECIFICATION:
<br />4 Weaver-Picatinny Rails
<br />Hardcoat Anondized-Aluminum Construction.
<br />One piece made.
<br />Quick & Easy Installation. 
<br /> Material: Aircraft Aluminum
<br />Finish: Black Anodized
<br />Length: (approx.) 4",7",10",12",15" 
<br />Weight(+ .750 Aluminum Gas Port Controller): 274g/347g/447g/625g/651g