Bathrooms usually have a depth of 20 inches, so 18 inches are most appropriate. Please measure twice before placing your order. Measure the distance from the front edge of the cabinet to the inside face of the cabinet back and then subtract 1. Frameless Cabinets do not require Rear Brackets. Face Frame Cabinets do require Rear Brackets to mount the slides.This can only be done within the first 15 days of receipt of the order. The item "Soft Close Drawer Slide 100 lb Ball Bearing Runners Full Extension 10 Pair" is in sale since Tuesday, September 05, 2017. This item is in the category "Home & Garden\Home Improvement\Building & Hardware\Cabinets & Cabinet Hardware\Drawer Slides". The seller is "decorhardware" and is located in La Puente, California. This item can be shipped to United States.