CECO Chrome Spline Drive Tuner Installation Kit (20 Lug Nuts & 1 Key) 1/2" R.H. Thread Pitch 1/2" R.H. 1.37" Overall Length 60 Degree Cone Seat 6 Spline Dual Hex 19mm & 21mm Key Tuner Style Lug Nuts are designed to fit small diameter recesses in Aftermarket Alloy Tuner Wheels that require a cone seat fitment. This type of lug nut has a 60 taper and should be torqued by hand only.