These are the same 10 degree steel valve locks that we install in our heads. They are of the highest quality we have found and made by a company that supplies most Nascar teams. Unlike the big box store brands these actually are heat treated correctly so they wont break and precision machined perfectly for repeatable installed heights. Available in +.050 height, standard and -.050 height.  Price is for 16pcs for 8 valves worth.