100% Foam Material: durable soft resin PU rubber. Ball diameter: about 42.6mm. Package Including :36 * Soft Elastic Indoor Practice PU Golf Balls Training Golf Balls(Yellow) and 1*mesh bag. Features:Soft, light-weight and flexible golf balls, ideal indoor practice sports training balls for the golf ball lovers. Use range:Suitable for indoor exercise and children practice as well. Great way to improve your short game in small places. The item is a set of 36pcs simple and practical golf balls, which are mainly made of durable soft and elastic PU rubber material, and soft and safe; Therefore, those PU golf balls are suitable for indoor exercise and children practice as well.