Hirose #HSH-31(B). Same as Consew #13086, #12009, and #12032
Singer Hook # 238250
For Singer 21W180, 46W61, 47W62, 47W63, 51W, 52W30, 52W31, 110K, 110W, 131W, 136W, 138W, 153K, 153W Class machines.