Universal Round Magnets Excellent for Uneven Surfaces Perfect for Arts & Crafts, DIY, School, Home, and Office Heavier Objects Will Be Held by Thicker Magnets Adhesive Foam Density 4 mm 8 round magnets in a pack, each with 4 buttons that measure 19 & 13 mm, or.75 in. and.5 in. See www.Promagproducts.com for Inspirational Thoughts Designed in the USA