I used these on a twin mattress, on a day bed, to hold an extra wide 2" foam pad (as well as a mattress cover on top), tight around the front edge of bed, so it makes a more comfy sofa against your knees than the mattress itself, when not used as bed. The foam pad did not want to make a right angle bend along the long side, but I snapped the mattress cover (pad underneath) to edge of mattress in 3 places with these 'suspenders' and now it's a tight rounded bend. (I'll just put the sheets on top of the mattress cover, leaving these 'suspenders' in place all the time)