Plastic winder, string length 30m, use: marking transitions - lines in construction, painting, SDK,..., after filling with the enclosed powder (blue - can be ordered additionally: blue 37096, light-blue 37094, red 37097, light-red 37095, black 37098), procedure: fill the winder with the enclosed powder, color it by shaking it and repeatedly extending and re-winding the string, then two of us stretch the string in the required place to mark the line and lightly strum - this applies the powder caught on the string in a thin layer to the marked material, then we wind the string, or again we add powder, packaging: blister with euro hole.