Constructive Playthings Crystal Bricks 136 Pc. Preschool Sized Building Bricks Set for Kids These transparent, plastic bricks are perfect for hours of building fun! Use them on your light table for an added element of fun. The translucent nature of the blocks allows the light to radiate through. Children can stack the blocks to see the colors mix and bring their creations to life. Compatible with most preschool sized building bricks