Not exactly sure of material... somewhere between Rubber and Foam. Like a poly mix. Some light bounce to them when dropped but not quite Rubber ball bouncing. Some light staining Approx 1 inch diameter ***Disclaimer on old/vintage/antique books/paper and the like: Some wear from age, use and storage which may or may not include some, none or all of the following: writing/personalized notes on inside covers and title pages(or notes on pages in the case of songbooks and sheet Music), small tears, creasing, etc.... all typical Vintage and antique book wear. Paper/prints: Opposite side may or may not have related or unrelated texts or prints which I have deemed less interesting than the one presented. Your opinion may differ See top of description for any outstanding flaws. **All items pictured are fully usable and/or functional unless otherwise noted** Inspect pics closely and ask any questions before buying or offering. Tons more toys, collectibles, paper, antique, vintage ephemera, maps, engravings, prints, vinyl, vhs, media, books, bags, handmade and more! Will combine shipping!