There is a slied underneath that straightens it out, but I have decided to go with one of my earlier versions which is more a traditional bed with sliding extensions. This is very light but I have a few problems with binding on the rear focus. The other prototype had no problems with very smooth movement. Just adds about 1.5 to 2 lbs to the weight. Still keeps it at 17lbs, but I really wanted to have a sub 15lb full extension 11x14/7x17/8x20 size camera. Easy to do if you keep the bellows length to about 27 inches. Its that next 18 up to say 45 inches that forces the additional wieght.