Liner Lock for Beaded Pool Liners (4 Feet) Liners can jump the track or fall out of the bead receiver for various reasons.These include improper fit of the liner, corner stress, liner shrinkage, stressed or expanded liner tracks, water behind the liner, etc. This can be a huge hassle and can even This can be a huge hassle and can even cause damage to your pool or liner. Using our liner lock you can prevent your new beaded liner from slipping out of the coping. Liner Lock can be installed and removed within minutes!