DL0011Da-Lite"s Carts give the lasting performance and quality you expect. All are designed to take the rigors of heavy use for years to come. You"ll also appreciate the attention to safety with no-slip pads, one-half inch safety lips and no sharp edges. This unit comes with 5"" casters, which are able to handle heavier loads, rather than the standard 4"" casters. Made with aircraft quality casters and o-rings for smooth, quiet operation and with a powder coated finish. Pre-assembled for convenience and robotic arc-welded for added strength. Cabinet models offer secure steel enclosure with hinged locking door. Fixed center shelf on all except for AV6C which has adjustable center shelf for components.