Viga High Quality Abacus Heavy Wooden Frame with Metal Sliding Rails - Space Saving Design - Easy to Move the Beads Heavy wooden frame with metal sliding rails Bright coloured wooden beads Size: 310mm x 310mm The metal bar dosen't warp and it's easy to move the beads! Safety: All Viga toys are made with non-toxic paints & inks and comply with EN71 & ASTM toy standards.