ECR4Kids Natural Hardwood Curved Play Tunnel and Arch Blocks (20-Piece) Creative Playtime  four sizes of curved blocks for kids to build tunnels, arches and other imaginative structures Variety Pack  set of 20 blocks includes8 small, 4 medium, 4 large, and 4 extra large arches Solid Wood Design  all blocks are sturdily built with 100% rubberwood with a natural finish Fine Motor Skills  little ones develop motor skills as they lift, stack and arrange arches Certified and Safe  GREENGUARD[GOLD] Certified for minimal chemical emissions into indoor air; features rounded edges for safety Block Dimensions  X-Large: 11" W, Large: 5.5" W, Medium: 3.75" W, Small: 2.2" W; all blocks are 10" L and 5.6" H Ready for Play  blocks come fully assembled