This is a new out of package gear reducer. The ratio is 1:10. The drive shaft is 12mm diameter, and the driven shaft is 17mm diameter.
There is no measurable backlash in this drive. The item "Gear Reducer Gear Box GONG TZYH Speed Reducer TKB50" is in sale since Monday, October 24, 2016. This item is in the category "Business & Industrial\Automation, Motors & Drives\Mechanical Power Transmission\Gearboxes & Speed Reducers".
The seller is "meeko1948" and is located in Massachusetts. This item can be shipped worldwide.