Box of 100 Large Capacity M Size Aluminum Bobbins for Tin Lizzie Quilting Machines. M size bobbins measure 1" in diameter and 3/8" thick. Aluminum bobbins are considered the Top-End "Luxury Bobbins". They offer less resistance which translates to less drag to the bobbin thread tension. Works with Tin Lizzie 18"LS & 26" Ashley, Queen Quilter 18", Handiquilter HQ Sixteen, Baby Lock Jewel 18", Pfaff Grand Quilter 18", Viking Mega Quilter 18" Machines & Frames.