The chalk cartridge set from Prym is suitable for tracing, writing and marking on almost all surfaces. The refillable cartridge holder can be used not only to make exact line marks, but also to make dotted markings. At the upper end of the cartridge holder there is a knob with an eraser cartridge; press the retaining mechanism on this to change the cartridge. 8 white and 8 coloured cartridges, the chalk cartridge holder and a special sharpener for the chalk cartridges are all included. The cartridge holder is supplied containing one white cartridge. The cartridges are economical in use and are supplied in protective packaging for transport.