This is a Grenada OHMS Cover. It was sent to the Cleveland, Ohio on 8/16/1900.
What makes this cover interesting is the OFFICIAL PAID HANDSTAMP CIRCLE in Black. It also is endorsed on the lower left with an M/S G.P.O. GRENADA, and there is a Cleveland Receiver mark on the back.
Included with this lot is a copy of a 1972 article in the British Caribbean Philatelic Journal by W. Danforth Walker.