Star Trek TOS 3rd Season Starfleet Engineering Patch Embroidered Starfleet Engineering Officer Patch! From Season 3 of Star Trek: The Original Series ! Add to your Starfleet uniform! This patch was worn on uniforms of Engineering and other series personnel in Star Trek: The Original Series . This patch is beautifully embroidered with great detail and will put the finishing touches on your uniform. Patch measures 3 1/4-inches tall x 2-inches wide.