Mersen DO fuse-links, also called Neozed type, are 400 Volts AC rated with 100kA interrupting rating. They have 3 physical sizes, DO1, DO2, and DO3 and fit into special screw caps. All fuse-links have blown-fuse indicators which are visible through the screw cap when mounted. Screw caps fit onto single and three-pole bases which are screw or DIN rail mounted. Accessories such as covers and gauge rings are described.