Unlike single hook spanners, GMT collet chuck wrenches have multiple splined teeth for secure gripping of ER collet nuts. The ER16-SLIM wrench is designed to fit our slim-nut ER16 collet chucks, which provides added clearance over standard hex nuts. The ER25-STD and ER32-STD collet wrenches fit our standard 1-piece collet nuts (castle nut) for ER25 and ER32 collet chucks.
Our CAT40 pull studs (retention knobs) are manufactured from high strength alloy steel. After turning, they are hardened, triple tempered, precision ground, and finally black oxided for durability.