Rumber is the trade name for rubber lumber.  It is used just like treated wood when a trailer is built, but there is no need for rubber mats.  It is tongue and groove, 2" thick, and has a 20 year limited warranty.  More than half the trailers we sell have Rumber flooring as a welcome option.  It makes keeping the trailer clean so easy - no heavy mats to drag in and out.  Just turn the hose on it.  The surface offers much more traction than rubber matting.   We love it, have a personal trailer with Rumber floor, a two horse that gets lots of use,  and couldn't be more pleased.   It is an optional feature with most brands, but costs less than replacing rubber mats just once.

I needed to add that there is NO wood in Rumber.  It is solid rubbery stuff made from recycled tires and milk bottles.

I had rumber in my 2000 3 horse GN and now in my 2005 LQ. It works great. As the poster above said. No need to mats.  Easy to clean and held up very well.

It is made from recycled tires and is a rubber material that is formed into various shapes. My trailers had 2x6 tongue and groove planks on the floor and 1/4" maybe 3/8" sheets on the walls. The sheets have a pebble grained texture, the planks have slight grooves. It gives the horses good traction.  I usually threw a bag of shavings in my trailers to asorb urine and would sweep it out every month. And two or three times a year I would hose it out good. After 5 years of heavy use, it still looked great. A few of the grooves were wore down right under where the horses stood, but the rest looked like new.