Warning: Choking Hazard - Small Parts. Not for children under 3 years.PreK - 2. Make learning truly hands-on with this phonics pebble set, ideal for introducing letters and their sounds! Develop letter recognition, word-building, and blending skills with these tactile pebbles. Cast from a unique stone mix, these durable pebbles are ideal for use inside and out. Includes 64 pebbles covering 44 phonemes. Teacher guide included. Each pebble sized at 1.5" each.