Ampco Box End Wrench, Aluminum Bronze, Natural, Head Size 5/16 in, 3/8 in, Overall Length 7 3/4 in

Nonsparking box-end wrenches won’t spark during use and are suitable for use in flammable environments. They contain no iron, are nonmagnetic, and are suitable for use with magnetic resonance imaging (MRI) equipment. These double-end wrenches have a different SAE (inch) size for use on two different size fasteners. The enclosed head on each end of the handle provides more contact to the fastener and allows more torque than an open-end wrench since the box end is less likely to slip off the fastener.