Pen, Centennial - RARE Singer (Vintage Original) mechanical it is the Throat Plate

it is the Throat Plate that is model-specific

If the spring and stop washer are in correct position

The right edge is 1/4" from the center needle position which gives you a scant 1/4" seam allowance

ES242*** indicates an original production commission date of January 10

Pen, Centennial - RARE Singer (Vintage Original) mechanical it is the Throat PlateThis pen commemorates Singer's 100 year anniversary in 1951. It features a floating little Singer sewing machine on the inside that sits on a sewing cabinet. Made by the Secretary Pen Co. of Union, NJ. It is in good condition, but it is likely out of ink as it does not write anymore, and it is missing the cap w clip.