The Sinar LC Shutter/4x5 Adapter is used by the LC shutter when the Sinaron Digital DB lens is mounted inside the bellows.The Sinar LC shutter can be directly attached to the adapter ringThis 4 x 5 adapter is clamped on the front side of the Sinar auto aperture shutterThe LC shutter/Sinarback adapter cable is used to connect the LC shutter to the Sinarback or its adapter plate