GRABOBBIN Magnetic Bobbin Holder Lower Looper for Juki Industrial Overlock Sewing Machines. Juki part # : 118-99307 For Juki MO-2400, MO-2500, MO-3600, MO-3700, MO-3900 series overlock sewing machines. Lower Looper for Juki Industrial Overlock Sewing Machines. No more runaway bobbins unwinding as they go. Grabobbin holds each bobbin tightly on its rim. This product easily displays thread colors on each bobbin and allows instant easy access. 8" plastic rack with magnetic strip includes one metal bobbin. Holds approximatley 16 bobbins. For steel bobbins only. Color may vary.