Hospital Bed Cot Sides - Box Frame 4 Bars.Clamps fix directly to box section bed frames.To accommodate users who have an extra high mattress or a pressure relief mattress on the standard mattress.Chrome plated steel rails.Telescopic rails.Spring loaded buttons on clamps.Gaps of 10.2 cm (4") between rails.Hard wearing.Rails are very secure.Satisfies medical device requirements. Easy to adjust. Length can be adjusted to fit various sized beds