The patent pending SI UDC 308 enables users to attach and detach the cover in 5 to 10 seconds with ease (stock dust cover will take more time to remove)! It is constructed of a high-density polymer making it more durable and functional than the traditional dust covers. The Ultimate Dust Cover features an adjustable detent set screw in order to compensate wear on the receiver and increase or decrease opening power (To adjust detent: use small flathead driver and depress the ball detent and adjust as necessary.). Choose multiple designs to customize your AR! NEW features of the Ultimate Dust Cover Enhanced Version include the added cut-out window on the rod for easy disassemble and that it has been made thinner than the original weighing in at only 0.4oz! Additionally, The "True Seal" Lip has been slightly modified to provide an even better seal than ever before!