here is the link to the motors i used
this is the model you want GH810136V3
its the 100rpm one you want
and this is the site link
http://www.gizmoszone.com
please note the "L" version may run at 50 rpms but is also longer due to more gears that is why i recomend the 100rpm version still slow and powerfull and a better case (both have the same torque output )