This is one MIP #1618 Traxxas Revo Center Drive Outdrive with set screws. Overall length is about 22mm, diameter is about 14mm, hole diameter is 6mm. The package had been opened and it appears the set screws have been used yet the outdrive looks new and not used. I re-stapled it after taking the photos. It's in a shopworn package from a hobby shop that recently closed. See the photos for the condition, more description, and what's included.