steel ring mandrel is perfect for forming and sizing rings from 12.37mm (US
size 1) to 23.8mm (US size 15). It has 1/4 size increment markings etched into
the side. It is smooth all the way around, so it is great for hammering all
sorts of metal on, as well as forming wax, PMC, or wire rings. Overall length
is 11.38” (29 cm).