Aluminum Stock picker Carts combine the mobility of a cart with the convenience of a step ladder. Spring loaded steel step ladder holds the cart securely in place while a person is standing on the ladder. The rubber tip ladder plungers down to prevent the cart from moving while stocking. Springs then return the ladder to the raised position once the person steps back on the ground. Standard shelves have a 2" lip turned up to prevent items from falling off. Standard casters are 4" x 1-1/2" mold-on-rubber, two rigid and two swivel with wheel brakes. Steel units have a baked-in blue powder coat finish for added durability. SPA model steel ladders have a baked-in silver powder coat finish.