OKUMA 1 Sq (2" slot) Lathe Turning Tool Holder Tooling Block 80mm X 45mm BHP 1.0
I believe this to be most similar to the OKUMA A118-8311 or the HAAS HSL30-8311 tooling block. Bolt hole pattern: 80mm x 45mm. This tool block is missing 2 of the coolant screws.