New Sewing Machine Thread - Small Spools White = Dia Feather Polyester #50 Black = Dia Feather Polyester #50 Each color: 1 bobbin x 4 pieces = 8 pieces total. Approximately 45m per spool. ◎ We consider 90% of the bobbin to be the winding amount, but please understand that there may be slight variations exceeding 90%. Regarding Use: Please adjust the amount of thread wound on the bobbin to suit your sewing machine. Bobbin Size: Diameter - Approximately 20mm Height - Approximately 11.5mm Hole - Approximately 6.2mm Material - Transparent Plastic Please be aware that these bobbins are for small spools. Only for those who understand the above information and the nature of the small spools.