This item is an Epica Star Drill Chuck with Key (model EP-20503).
Clamping Range: It accommodates drill bits from 1.5mm to 13mm.
Mount Size: Features a 1/2-20UNF threaded connection, compatible with most electric drills.
Mechanism: Uses a keyed design for securely tightening or loosening the jaws to hold bits firmly.
Usage: Suitable for both forward and reversing drills.