Pure Stainless Steel. Insertable for small is length is 55mm, diameter tapers from 15mm down to 10mm.  Has a jewel decoration on the handle. 

Medium is  Length is 83mm, diameter 3.2mm.

One picture has complete measurements and one is next to standard #2 pen for size perspective.

 NO electrical connection present, but can be easily added with items from our Do-It-Yourself section. A small pad or gator clip is the simplest. For other how-to ideas and instructions, check out the forums at smartstim.com.