Consists of Six matching pairs of wooden pressure cylinders with holding tray. The wood-coloured pistons on 6 of the tubes correspond in pressure to the black-coloured pistons on the other 6 tubes.
1. Includes 6 cylinders with wood-coloured pistons and 6 cylinders with black-coloured pistons, and Wooden holding tray.
2. The object of this material is to match the wood-coloured piston tubes with the black-coloured piston tubes of the same pressure and align them side by side in the holding tray to make up the 6 pairs of tubes.
