The Uncarved Block Ergo Wrench fits perfect in either hand and has a rounded tip to reduce time spent lining up the wrench in larger holds.
Complete with a 5mm hole to attach some cord which will allow you to hook it on your harness with a carabiner for route setting. Color will be random.
The Large Ergo Wrench fits all standard imperial 3/8" Socket Head Bolts and size is 5/16".
Want to use a drill instead? Just get the 5/16" straight ball-end hex key here.