Riflespeed RS87 Gas Controls Wave Spring Stainless Steel. If you want to significantly increase the amount of force required to adjust the gas setting on your RIFLESPEED Gas Control you can nest a second Wave Spring with the Wave Spring currently installed on your Gas Control. This doubles the spring rate and makes adjustment of your Control Knob significantly more difficult. Specifications for Riflespeed RS87 Gas Controls Wave Spring: Manufacturer: Riflespeed Color: Stainless Fabric/Material: Stainless Steel Size: One Size Last Chance: Yes Package Contents: Riflespeed RS87 Gas Controls Wave Spring Riflespeed US0117: RS87 Wave Spring Stainless Steel