Lingerie type wear, or possibly could be attached to daytime casual or dress wear.

Nicely done, no flaws noted in the stitching itself.  The lower edge has some roughness to it that may indicate past attachment.  Still these stitches are tight and intact.

Measures 17 inches from side to side.  

Side seams or side edges actually, measure 4 and 1/2 inches

Top edge to bottom edge, at the longest point, measures 10 and 1/2 inches.  This includes the shoulder strap.  The shoulder strap alone measures 6 inches.  

The bottom section measures 4 and 1/2 inches top to bottom, just like the 'side edges'

Put the creative spirit to work in the vintage piece of yesteryear!

Crochet cotton thread.  

Lower edge could be carefully sewn onto fabric, if desired

Stitches appear to be tight and intact.  It could appear to have been worn then this section taken off to be attached to another like garment.

Smoke free home.  No odors or contrary smells from this piece.  Appears clean.  Expectations for this to be able to be gently hand washed.

Thank you for looking!