Liner coping simply installs on top of the pool wall and holds the pool liner in place to prevent it from slipping into the pool. It's good practice to replace these items when changing a pool liner as they become cracked, brittle and beat up over time. Don't get stopped in the middle of your liner change because of crumbling coping. 18' X 33' Oval Kit includes 44 flat coping strips that measure 24" long.