Easy-to-use E-Z Lock mechanism provides secure and stable installation. No tools required. Adds 5 inches to height of toilet. Easy to clean design fits most standard and elongated bowls. Provides assistance for those with bending and sitting difficulties. Measures: 15 1/2 inches W x 17 inches D x 20 inches H (39.4 cm x 43.2 cm x 50.8 cm). Same as above with the added feature of arms for extra stability Armrests are padded for comfort 15.5"w x17"d x 20"h Width between arms is 17.25"