Possibly SINGER Sewing Machine Attachments for class 503 machines

Vintage Singer Sewing machine Attachments for 503 special Slant-O-Matic in box

Singer Sewing Machine Attachments for Class 503 Machines 161745 Original Box USA

Vintage Singer Slant O Matic Sewing Machine Attachment 503 Special W/ Box Manual

Vintage Singer 503 Sewing Machine Attachments

Vintage Singer Sewing Machine Attachments class 404 Part No. 161277. H

Singer 503 Slant O Matic Sewing Machine Attachments

Vintage Singer Slant O Matic Sewing Machine Attachment 503 Special W/ Box Manual