Classic ViewMaster - Yellowstone - North - 3Reel Packet -21 3D images - from the 1950s 3 reel ViewMaster set -1950s views of Yellowstone - North - Mammoth and Canyon Areas Mint Unopened - New You will need a ViewMaster viewer to view the reels - available here on Amazon. Click on 3Dstereo Logo for largest selection of Quality-Grade ViewMaster, classic, vintage, & new