Ceramic Ring Soldering Stand - SFC Tools - 54-120 The ceramic ring stand has a heavy metal base and heat-reflective 6" (15cm) tapered ceramic ring mandrel. The mandrel fits in a steel clamp that is mounted to the base and has double swivel action. The swivel action easily allows exact positioning or whatever angle is desired, enabling the user to work with both hands. The smallest ring this tool can hold is a size 4, or an inside diameter of 14.9 mm. Measures 7 x 4.75 x 2.5 (17.8 x 12 x 6.4 cm).