The Quantum FW-45 2-Step Motor Drive Cord is designed for Mamiya 645 AF Cameras.The Freewire Mamiya 645 AF Two-Step MD Cord helps to keep your camera meter and focus function continuously “on.” Thus, your camera will be ready for instant shutter releaseThe alternate option is to select the motor drive “delay” to command your camera to “wake up,” focus and meter, then release the shutter