Amazon.com : D5600 Viewfinder Eyepiece Eyecup Eye Cup for Nikon D5600 D5500 D5300 D3500 D3400 D3300 Digital Camera [2Packs], Replace eyepiece DK-25, Fire Rock Camera Eyecup Accessories DK25 : Electronics
Upgrade Nikon eyecups model D6 D5 D4 D500 D850 D D810 – Hoodman Corporation
Amazon.com : D5600 Viewfinder Eyepiece Eyecup Eye Cup for Nikon D5600 D5500 D5300 D3500 D3400 D3300 Digital Camera [2Packs], Replace eyepiece DK-25, Fire Rock Camera Eyecup Accessories DK25 : Electronics