This review from The Firearm Blog contains info on the crush washers as well as the CompTek products.
New design features an interior groove to allow the washer to collapse and deliver consistent torque throughout the full range of movement. This model is machined from 17-4 PH Stainless Steel and is shipped with a machined finish (no plating). Designed to provide 1 full turn after contact when used on barrels with ½-28 threads. Use to align your muzzle devices without applying excessive torque to the barrel threads as is common with conventional crush washers. Provided torque is approximately 15 lb-ft. Do not reuse - remove and replace. Crush washers install with the angled side against the barrel and the flat side against the muzzle device. Shipped with installation instructions.