Cardboard mounts for picture framing | See our many craft products here
Amazon.com: Bright Creations 50-Pack Self-Stick 7 in Cardboard Easel Backs, Picture Frame and Art Easel Stand Bulk Pack for Photographs, Artwork, Posters, Signs, and Craft Projects (White)
Cardboard Picture Frame Corner Protectors F7 - 14mm x 44mm x 40mm
CARDBOARD PICTURE FRAME | DIY frame out of cardboard - YouTube
Cardboard Pre Cut-Frame A3 10 pack – Educational Art Supplies
Father's Day Cardboard Photo Frame Craft - Red Ted Art - Kids Crafts