Snowfeng Portable Bed Sit-ups Fitness Equipment for Belly Abdomen Exercise Lose Weight Perfect gift for friendsespecially for those who doesn't have time to do exercise outside Fix it on both bed mattress and bed edge. Just as the picture shown, put the metal clip on the bottom edge of your bed. The metal clip is connected with an adjustable band which makes this sit-ups suits most beds. Height of ankle bar is adjustable. Easy to carry and install.