The EDX 2 and EDX 3 are SLRs marketed by Ihagee (West) c.1978. These are rebadged versions of the Topcon RE 200 and RE 300, respectively. Please see those articles for more information.
Having the Exakta name on a Topcon body comes full circle: Tokyo Kogaku's original SLR the Topcon R adopted the Exakta bayonet mount in 1957, although not its left-handed PAD aperture actuator. Over the generations the Topcon mount added several modifications, in particular with the innovative Topcon RE Super to enable open-aperture metering. It is this modified Topcon RE mount used on the EDX models, as noted on the last page of the manual linked below.