TOYO QS adapter have a carriage that slides a digital back or roll film back and ground glass in and out of place for fast change from ground glass focusing to shooting. Built-in dark slide engages when ground glass is in film plane. Fresnel lens and acid etched focusing screen are included. Accepts all 6x7cm and 6x9cm graflok type roll film backs including TOYO 180-719 model fits all Toyo 4x5 cameras and all brand 4x5 cameras with international graf lock type backs by simply removing the ground glass frame