The thumb plate is detachable on our Arc Jet compasses and an extra thumb plate will replace worn out or lost ones.
The thumb baseplate on the Arc Jet compasses has a unique design with a cut-out to provide perfect contact between thumb and map, and an attachable thumb plate for those who prefer the more classic thumb grip.
Simply slide the thumb plate on/off to the baseplate with a simple click, try it out and see what you like the best.
The thumb plate fits all Arc Jet compasses with the exception of Arc Jet C.