These are plastic ice cube trays from the $1 bin at Target; the bottoms of the trays are rubber, so you can push the bottom inward. On the outside, I wrote different phonemic awareness & phonics concepts (1. Consonants, 2. Consonant Digraphs, 3. Glued Sounds, 4. Vowel Digraphs & Diphthongs). Some activities are: teacher saying a sound and students find and press the corresponding letters, hold up a word card and students say sound and press "button" with the letter combination you are reviewi...