This English concertina is a George Case design, and his patent was leased by Boosey & Co. Boosey made instruments throughout the England in several locations. Mr. Case was a musician and professor. Chris Flint (2010) has written a concise biography of George Tinkler Case.
This particular box was made on Regent Street in London. That workshop was active from 1864-??. It is one of the later concertinas in the Case line, as the greatest serial number know is 5004. 3908 is lower than the lowest number known produced at the Regent Street location (Flint, 2010), suggesting it was one of the earlier boxes produced at that location.
I purchased the box from John Castiglione Accordions in Michigan, US. I suspect that he passed it on due to the amount of work it needs and that he’s running a business. Hopefully, I’ll be able to do it service.