Our new stainless steel 'Snapbackā throttle return springs wrap around the end of the Stromberg throttle shaft and hook onto your linkage lever arm to snap your carburetors shut. Easy to install, they fit our 9090K and 9091K kits, and other carb lever arms. They're chemically blacked too, so they all but disappear from view. They're standard fitment with all Genuine Stromberg TwoStep linkage kits.