WE JUST BOUGHT AN OPEN RANGE AND THEY ARE LIGHT WEIGHT IN PART TO THE SLIDE MECHANISMS. THEY ARE GREAT!! WE LOVE OURS! THE OTHER THING IS THE LEVELING SYSTEMS, IT IS AWESOME. VERY LUXURIOUS. THE MAN THAT IS MFG. THESE WAS A DESIGNER FOR KZ, KEYSTONE, AND NEWMAR. HE ACTUALLY INCORPORATED ALOT OF...