Class 66 bobbins have slightly curved tops and bottoms and are for top-loading bobbin cases.

These bobbins are suitable for select Singer, Baby Lock, Brother and Simplicity machines. They are not suitable for Bernina, Elna, Husqvarna/Viking, Janome /New Home and Pfaff machines.

Pack includes 4 plastic bobbins that measure approximately 3/4" in diameter.