Singer smooth & even feed sewing machine foot Style C-470. What it is, is a low shank walking foot attachment for Singer Zig-Zag machines of the time, except for the model 223U (for some unstated reason).

It came with the cardboard box that has a $4.95 price printed on it.

The outer box contained a plastic box that contained the attachment and a set of instructions

…and here are the instructions.