Bolt sizer, Metric & Imperial

thingiverse

This handy wall-mounted tool serves as an indispensable reference for verifying the sizes of bolts and nuts at a glance. Conveniently featuring separate spaces for both metric measurements and two distinct types of imperial measurements – coarse and fine – it proves to be an invaluable asset in various settings, albeit it neglects BSP, gas fittings, and other obscure components.