I love this ramp and own two of them.  One of them has been in constant use for 5 years and (aside from a little dirt) is just like new.  These ramps are truly built to last.  It is a nice heavy weight which makes it stable underfoot.  The treads make it safe for the dogs even when they are at a dead run.  I use one of these outside the doggy door to span a 2 1/2 foot drop.  The dogs love it.  It is more expensive than many other ramps, but it's worth the money.