Genuine Hafele product
Forms accurate, high strength joints in soft or hard woods, plywood, composition boards and other timber. 
Much faster and more precise than dowelling. 
The biscuits are made of compressed laminated hardwood which expands upon contact with a woodworking adhesive.

No 0 (47.5mm x 15.5mm x 4mm) thick for board thickness 8mm to 12mm.
No 10 (53mm x 19mm x 4mm thick) for board thickness 13 to 18mm.
No 20 (60mm x 23mm x 4mm thick) for board thickness 19mm plus.