Review on Adjustable Bed Sheet Holder Straps - Fitted Sheet Clips with Elastic Gripper Holders for Bed Sheets, Mattress Covers, Sofa Cushions (Set of 4) by Erica Nelson

I installed them myself on a king mattress in five minutes. The mattress does not need to be removed. Simply clip one side, then pull the loose end from the corner of your head or leg (outside the mattress, not under it) to the other side, where you then angle it up and to the same height as the first clamp. I think the seller should provide more detailed instructions as the negative reviews seem to be from people who couldn't figure out how to install them. It is also very important that you increase the length BEFORE beginning the installation. The 4-star rating is due to the seller not providing sufficiently detailed instructions. These straps are excellent and very well made but if fitted incorrectly they will not function properly. I strongly suspect that a lot of the bad reviews are from customers who don't increase the strap length before adjusting. In many cases this will result in the straps exceeding their maximum span length which is clearly stated in the quick start guide.