Grab yourself the best, with a Faulhaber 47.6:1 Hybrid Gearhead, Part Number 22/6 47,6:1. For more specifications see:
http://www.faulhaber.com/uploadpk/EN_226_MIN.pdf
This 47.6:1 Hybrid Gearhead suit Faulhaber DC-Motors 2224, 2230, 2232, 2233 and Brushless DC-Servomotors 2232 BSL, 2248 BSL. It is extremely light and compact at Ø 22 mm, it combines smooth performance of a spur gearhead with the high torque output of a planetary gearhead, it has smooth and quiet performance, it has a long operational lifetime, and low additional system friction (75 % efficient)
I have two of these for sale, as well as some other Hybrid Gearheads (34:1), and 2 x Faulhaber Series 2224 DC Motors. Check out my other auctions, and get these all for a steal!!
Let me know if you have any queries.