9 Pc 1/4", 3/8" and 1/2" Drive Wobble Extension Set 3-  drive 2, 4 and 9 length, 3- 3/8 drive 3, 6 and 9 length, 3-1/2 drive 2, 5 and 10 . Knurled extensions for easy non-slip grip. Wobble extensions give you 16 degree angle flexibility when clearance or control is a problem. Drop-Forged, chrome Vanadium Steel. Heat Treated, Chrome Plated.