DESC: Jr. Hollow Blocks by Guidecraft by Guidecraft 16 piece set constructed using Baltic birch and northern hardwoods. Edges are rounded and surfaces are sanded smooth for safety and hors of creative play. Blacks are sealed and finished inside and out. 54 lbs. set. Guidecraft smooth unit blocks are made to resist dents and dings. You'll notice the finely sanded and rounded to eliminate any sharp edges, and are splinter-free to protect tender young hands. All our blocks are guaranteed for life. Materials, Birch Ply, Hard Maple.