This is a nice original low shank straight stitch foot and thumb screw. It is part # 45321 and will fit Singer models 15, 27, 28, 66, 99, 101, 185, 192, 201, 206, 221, 222, 306, and 319. This product is available from Central Michigan Sewing Supplies.
Screw, Singer Featherweight Presser Foot Thumb Screw CHROME
Stitch Regulating Thumb Screw (New) for Singer 15 Class & 201
About Sewing Machine Shanks and Presser Feet
Blog & More Tutorials & Guides A Quick Guide to Your Sewing
Mystery Sewing Machine Foot - Threads
Renjyi Enterprise Co., Ltd.
Vintage Original Singer Low Shank Feet & Attachments – Central Michigan Sewing Supplies Inc.
This Original Singer Sewing Machine Straight Stitch Foot & Thumb Screw is an ideal fit for Singer sewing machine models 301, 301A, 401A, 403A, 404,
Original Singer Sewing Machine Straight Stitch Foot & Thumb Screw Slant Needle
1 PCS Sewing Machine Low Shank Straight Stitch Presser Foot For
Straight Stitch Hinged Foot and or Thumb Screw Sewing Machine
ZIGZAGSTORM 446014 Low Shank Snap On Presser Foot Kit
Singer Model 66 Sewing Machine Parts: Original and Replacement – Page 7 – Central Michigan Sewing Supplies Inc.
Zigzag Attachment, LOW Singer Automatic (Vintage Original
Presser bar – Vintage Sewing Machines
Bernina #64 Straight-stitch Hemmer Presser Foot 4mm (008483.73.00)