This is a fpv mount for the "Flyzone Calypso", "Hype Relax 2" or also called "Robbe Arcus 2".
It fits near the CG. The platform is big enough for the transmitter and a gps antenna behind the camera gimbal. The little round part is glued into the fuselage (behind the spar) and you can run your wires through into the cockpit. There is a M3 brass knurl nut hidden in this part so you can screw the fpv mount to the fuselage and if not needed you can screw the cap on it instead. You need a M3x15 hex screw. It might fit on other gliders too. You can heat up the legs with a heatgun and bend them into your needed shape.