The recording-translating device was a multi-function communicator provided to Captain James T. Kirk and the Gorn Captain by the Metrons, for use in their matched combat following the destruction of the Federation outpost on Cestus III in 2267. When struck against a lump of coal, the device also served as a useful firestarter, igniting the fuse that fired Kirk's primitive cannon at the advancing Gorn, disabling him. (TOS: "Arena" )