1" diameter anodized aluminum frame w/smooth gliding casters. Takes 1 to 4 side-by-side tiers. Equipped w/a bottom shelf & has rotating lever which locks chart-holders in place for noiseless movement. 5yr warranty #263810-1 Tier 37Hx13Wx13D #263820-2 Tier 37Hx23Wx13D #263830-3 Tier 37Hx33Wx13D #263840-4 Tier 37Hx43Wx13D UNSPSC#42142305