Dotco Q Indexable Quick Change Angle Head Options are indexable with quick release for use with 15L..Q Power Units. Known for it’s durability, dependability, and versatility, Dotco Q Indexable Quick Change Angle Head Options comes in Q5 Heads 90 Degree Heavy Duty, -Q6 and Q7 light duty/compact heads, Q4 Heads 45 Degree, and – Q9 360 degree head with 1/4”-28 internal thread for threaded cutters and 9/32”-40 internal thread for threaded collets.