This is ER16 High Quality Collet with 3.5mm Hole.
Made from Alloy spring steel and fully hardened
All critical collet surfaces are precision ground for accurate fit
Works in all ER16 Collet Chucks
ER16 collet has a full 3.5mm range of collapse while maintaining full accuracy
ER16 collet has a range : 3.0mm to 3.5mm