SAE combination Non-Sparkinf 12-point Wrench. Precision.machined openings for a perfect fit with nuts or bolts. Oval handle for a more comfortable grip. Super drive box-end design. Bronze-Aluminium Alloy. Tools recommended for 1, 2, 21 or 22 Ex zones. Opening size: 1/2″. Total length: 7″. Outside diameter: open end: 1-3/64”. Box end: 25/32″.