This is a deck mounted round flange used for a rail or ladder - with 1.9" outside diameter. It includes the bolt, but does not include the anchors which mount the flange to the concrete deck. Usually used for inground slides. Outside Dia. : 6-3/8" (Bottom of Mounting Flange) Outside Dia. : 2-3/16" (Top of Flange) Inside Dia. : 1-15/16"(Top Inside) Ht. : 3" There are a total of 4 mounting holes spaced evenly on the flange bottom. Center to center measurement of opposite holes is 5" Center to center measurement from one hole to next is 3-1/2"