Note: each group contains 12 plate clips and 12 plate frames. It is suitable for mattresses with a thickness greater than 3 inches (mattresses less than 3 inches only need a sheet clamp). It is suitable for beds without a bed box or with a height of less than 2 inches! It is not suitable for high elastic foam mattresses. Easy installation: it can be installed regardless of the size of the room, and there is no need to turn up the mattress. The secure and firm fixed mattress closely fits the mattress without sliding, and the mattress is more flat. Just lift the mattress gently and insert it into the snake shape of the L-shaped bedspread frame, lay the bedspread, insert the U-shaped clip into the convex round column of the bedspread frame, and the bedspread is clamped in the middle. Material: the 12 sheet clips are made of PP plastic, which is softened at about 155 and used at -30~140 . The 12 bedspreads are made of ABS plastic. The thermal deformation temperature of ABS material is 93~118 , which can be used for a long time within the temperature range of -40~100 . Please read the precautions, installation instructions and installation drawings carefully. The correct installation can better prevent the bed sheet from sliding, make the bed sheet better fit the mattress, keep the bed sheet flat and not sliding, and let you sleep well all night. If you don't know how to install it, you can watch the installation video several times or contact us to send you a slow installation video. According to your actual situation, select how many sets of retainers to install. After use, please keep the spare parts of the bed sheet frame set. The bed sheet clip can also be used as a snack clip.