The seller seems a bit confused, the patent is listed as 1872, the wrench as 1878, but the patent is in fact Feb 18, 1879, and is number 212,298....
Billings wrenches in general are not that rare, but, this one is interesting because it is a variation on the usual shape, and is marked both C E Billings on one side, and Billings & Spencer on the other.
The third mark of another company (G&J Mfg Chicago)* in the same type face is interesting also......
*Presumably Gormully & Jeffery, of rambler fame