戒指尺寸與塑形心軸 — 溝槽鋁製，英國尺寸 1–15，銀色

The grooves are deep enough that the ring doesn't slip even when I'm hammering a stubborn kink out, and the silver finish doesn't tarnish after a few weeks of sweaty workshop use. Sizing a shank against the half-marks takes seconds now.

The engraved half-size markings are crisp and easy to read even under a loupe, which saves time when truing a bent shank. It’s solid enough to handle repeated hammering without dents forming on the surface.

The grooves are deep enough that my ring doesn't slip even when I'm hammering it back into round, which was my main worry with a cheaper mandrel. The engraved numbers are also surprisingly easy to read in dim bench light, so I don't squint every time I check a size.