DD21 Series Power Entry Module (without filter) The DD21 series power entry modules have been designed for screw on panel mounting and come equipped with PCB terminals so the board can be mounted directly to the back of them. They have a C14 IEC appliance inlet. They have been designed to serve 3 functions. Firstly they offer appliance inlet protection class I. Second is a 2-pole line switch and lastly they have a built in fuse folder for 5x20mm fuses. They come with a V-lock notch as standard and have covers on the rear side.