Dividers bolt into existing holes in shelves. Available 137⁄8"H, which fit into shelving units as they are shipped or 87⁄8"H if you are adjusting shelf heights or adding a shelf. When selecting 137⁄8"H dividers for sections of shelving without doors, select the model numbers from the “W/O Door” column. For sections of shelving with doors, select model numbers from the “With Door” column. When selecting dividers to be used in the contoured back top section of 16”D Contour shelving, use model DC-161-C for sections without doors and model DC-161-CD for sections with doors (DC-161-CD dividers require drilling one hole for installation).