http://www.northwestrubber.com/horse_trailer_mats.html
http://www.cfmmats.com/Trailer_Mats.htm
http://www.thecrazyhorse.com/
http://www.rbrubber.com/
http://www.greatmats.com/products/horse-stall-mats.html
http://www.groupsummit.com/horses.html
I have summit mats and they have lasted me for about 15 years without cracking.