The handle is a 1/4" diameter tube of stainless steel. You insert the Triangle insert pieces into it and lock them in place with a screw. You can put the whole thing in the kiln for annealing. Handle length of 10". Requirements: The handle and insert are sold together because you need one handle for every insert you want to use during a torching session. You can't remove an insert while hot. You can buy other inserts, but know that if you buy them separately from a handle, you can only make as many cabochons as you have handles for, in each session.