I found this coin in a dealer junk box, and am uncertain if it is genuine or not.

Date: 1671
Diameter: 21mm
Weight: 1.72g
Thickness: 0.5mm or less
Metal: unknown (I think brass based on color)
I was able to identify it as a trade token from Brailsford in Derbyshire. The token is listed in Trade Tokens Issued in the Seventeenth Century in England, Wales, and Ireland by George C. Williamson (published in 1889). The citation on page 120 reads as follows:
32. O. WILLIAM . WEBB . OF = The Tallowchandlers' Arms
R. BRELSFORTH . 1671= HIS HALF PENY. W . W.
On my coin, the reverse says "A HALF PENY" instead of "HIS HALF PENY." but otherwise matches the description in the book. I assume the reference to Tallowchandlers' Arms is to the coat of arms at the center of the obverse. The book does not give any details such as the size or weight, or what it is made of, and does not provide a picture.
If anyone knows anything about these trade tokens, I welcome any additional information you can provide, including whether or not you believe it is genuine. I would like to add it to Numista, but only if it is genuine. There are similar coins listed under United Kingdom, Currency Tokens.
https://en.numista.com/catalogue/pieces55139.html
https://en.numista.com/catalogue/pieces18015.html
https://en.numista.com/catalogue/pieces64662.html
Best regards,
David