These SLR Rifleworks SD5 N.O.T.A.S. Faux Suppressors are primarily for SLR SD type Handguards, as a placeholder for a suppressor or use in states where suppressors can not be obtained. Features1.0" Internal bore works with any caliber5.375" in length (adds 4.75" to barrel length)7075 Aluminum with Hardcoat black anodize416 SS rear endcap with black melonite finishMimics the weight of most suppressors