2 years & up. Refresh your sensory materials with these sustainably made Tactile Matching Stones! Invite children to explore sequences, patterns, matching, categorizing and more. Children will experiment through a variety of activities like stone tracing, line drawing, stacking, and dough stamping. Tactile Matching Stones are versatile and provide opportunities for children to enhance their cognitive and fine motor development. This 24 piece set includes an activity guide and storage bag. Surface clean with a damp cloth. Pieces measure approximately 2"D.