Bought this for our 50-pound dog, for use following surgery, to reduce the risk of post-op hernia.  Trained him on it prior to surgery, since he's used to jumping in and out of the van.  Dog navigated it just fine, even in post-anesthesia haze :-).  Also used indoors to get him on and off the grooming table.  All surfaces are coated, so there's nothing to scratch the vehicle's paint.  When folded, ramp kept closed with a coil spring, protected with a bit of clear tubing.  Simple solution that works just fine.  Notch in rails well-placed to carrying when folded.  Rubber pads help resist slipping off the bumper when the dog is walking the ramp.  Definitely recommend to dog friends.