Strike Industries SIARARET7RED AR Advanced Receiver Extension AR Style Mil-Spec 7075 T6 Aluminum Red. Extension tube for AR-15/AR-10 receivers. Mil-Spec size, made from 7075-T6 aluminum with a red hardcoat anodized finish. Notable specs: Type Extension Tube; Model AR Style; Size Mil-Spec; Material 7075 T6 Aluminum; Finish Red Hardcoat Anodized. SKU ACC-STRK-ARARET7RED; Manufacturer Strike Industries; Mfg. Part Number ARARET7RED; UPC 708747546637. Not shipable to California, Illinois, or Washington.