10 Metal Bobbins. Fits the following models of Singer........

223, 237, 239, 293B, 1107, 1120, 1409, 1507, 1525, 1732, 2250, 2259, 2263, 2277 Tradition, 3001, 3002, 3003, 3004, 3005, 3011, 3012, 3013, 3014, 30215, 30518, 3116 Simple, 4001, 4002, 4005, 4006, 4009, 4011, 4012, 4015, 4016, 4019, 4022, 4166, 5102, 5107, 5123, 5127, 5400, 5502, 5504, 5505, 5508, 5522, 5524, 5525, 5528, 5532, 6180, 6199, 7312, 7322, 7350, 9910, 9920, 9940, 15-30, 15-88, 15-90, 15-91, 15CL, 15-125, 15-86, 15-96, 15-97, 15-87, 227, 331K1, 331K4, 331K5, 331K6, 331K16, 31-15, Scholastic, Scholastic Plus XL1000, XL2021, XL6000 

Bobbins measures 7/16" thick x 13/16" wide.