Elmer is an imager and spectrograph in the visible wavelength range for the Gran Telescopio CANARIAS, GTC. Elmer is being managed directly by the GTC Project Office, who has done the whole Preliminary Design and large part of the Detailed Design. This instrument shall operate at the telescope on Day One, as a back up in case of delays of the major instruments, guaranteeing the scientific return of the GTC. A brief presentation of the instrument is here given. The expected scientific performance of the instrument is summarized. Finally, the general description of the management strategy and project parameters are described.