ABC Spa Cover Roller Easy To Use & Install - Completely Assembled - Only Needs A Screwdriver To Mount To Spa 4 Rollers On Each Arm Make It A "Snap" To Slide On & Off - Cover Maybe Used As A Table Top While In Open Position Requires 1/2 Width Of Spa Cover Behind Spa - Fits Square & Rectangle Spas Folds Snug Against Spa While Not In Use - Manufactured Using The Most Durable Weatherproof Materials