The HB-81 is a lens hood designed specifically for the AF-P DX NIKKOR 10-20mm f/4.5-5.6G VR lens. It is used when shooting with the lens on an FX full frame camera at the telephoto end or when using through the entire zoom range on a DX format camera. The Lens Hood and Lens Cap can be taken off the lens, or placed on the lens as one unit, or separately.