Made of iron and zinc plated surface treatment, anti-corrosion and durable to use.Each Picture has two pronged "legs" that enable it to be attached to a wood picture frame without screws or nails. Nailess Picture hangers install very quickly into hard wood - pilot holes are usually not necessary except for very hard woods like oak or ash.These fasteners are secured to the item by tapping in the 2 prongs into the wood with a hammer. Fast and simple installation.Easy to use and work well on small wood picture frames, stretched canvases, framed photos, bulletin boards, framed posters, framed diplomas, wood craft projects, pallet wood projects. Specification:Material: IronFinish: Zinc PlatedThickness: 0.8mm / 0.031""Leg" Length: 10mm / 0.39"Total Size: 50mm x 8mm x 14.5mm / 1.97" x 0.31" x 0.57" (L*W*H) Package Content: 50(+/-2%) x Nailess Picture Hangers