7/8" dia., 5/16" between flat flanges. For Pfaff 130, 229, 230, 260, 360, 300, 332, 232, 138, 238, 1222, Calanda 3000, Bell 501, Adler 189, 189A, 289A, 589A. Commonly referred to as Style H.
they 'e e3xactly what I expected and needed - except I ordered wrong size. Check before you order. Now have to return for right size. They have been very nice about that too.