Woodtek 160556, Hardware, Furniture, Chair Swivels, 6-1/2" Square Chair Swivel Black All steel construction with black ed (electro deposition) finish. Specifications: Bore Diameter=5/16 in, Height=1 in, Length=6-1/2 in Specifications: Material Thickness=.08 in, Material Thickness=2.0 mm, Mounting Hole Center To Center=5-1/4 in Specifications: Taper degrees, Weight Rating=600 lbs, Width=6-1/2 in Specifications: Center To Center=5-1/4 in