7/8" coins and 1.25" squares. Each set holds 1/4 lb (pound). For holding on 4 corners, 4 sets consisting of a coin and square each are required. No damage to walls, adhesive removes cleanly. Ideal for hanging educational items, posters, charts, signs, and more. Easy-to-use, indoor only. Adheres to smooth, painted surfaces, metal, glass, and more.