The Leclerc bobbin winder is all-metal except for the wood handle. The gears are completely enclosed, which prevents any yarns from getting caught in the gears during winding. The mechanism sits on a special permanent greased bushing. The winder clamps to a surface with a built-in screw clamp. Once in place, the shaft runs perpendicular to the surface edge. The tapered plated shaft allows a variety of bobbins to fit:
- Leclerc, Schacht, and Harrisville bobbins
- Leclerc pirns (but not Schacht or Bluster Bay pirns)
- Leclerc plastic spools (but not cardboard spools)
- Bluster Bay paper pirns
The turning ratio is 1 : 7.5.