I built a FEL for a garden tractor and used these in place of hydraulics. As far as strength they are extremely strong for the size. Speed is very slow but they have a massive gear reduction, so keep that in mind when mounting them to get as fast of movement as possible. Im running them on 24v and so far the motors have held up. Thats the good. The bad- they arent remotely close to water resistant there is not a single seal on these units and 2 the picture in the add of the internal gears is not even of these units. The internal gear connected to the worm gear is plastic and is held in place with tiny roll pins to the end of the shaft. I was extremely hard on these and broke 3 and decided to take them apart and found the roll pins completely crushed and the gear spinning on the shaft. I drilled out the gear and shaft and installed bolts in their place and epoxied the damaged areas of the gears and sealed the units on the way back together. so far they have held up beautifully since then. For 50 bucks though I am very impressed.
Seth 
