Jumbo Metal bobbins
The metal bobbins are 1.4x larger than the standard Janome bobbin, hold 40% more thread, and are for use with select models listed below:
Part #761094115 is compatible with the following models: 1600P-QC
Part #761094104 is compatible with the following models: 1600P, 1600P-DB, 1600P-DBX, MB-4 (original version not S), MB4N, MB4N V2
Part #770591001 is compatible with the following models: MB4S, MB4SE, MB-7 Original, MB4S V3