DL Series Pre-Earth/First Mate last Break connectors are engineered to provide a path for any stray voltage to be shunted to a safe ground so that the operator and voltage-sensitive equipment may avoid harm. They are suitable for applications where a protective circuit from the shell to a safe ground is a safety requirement, such as factory automation/process control, and machine tool.

The connectors are made with a pre-earth contact, grounded to the shell, that mates first and provides protection from voltage outputs. The product is designed so that during the mating cycle of the plug and receptacle, the longer socket contact in the plug makes electrical engagement before the rest of the contacts mate, circumventing harm to electronic circuits or users.

Connectors are described as intermateable with MIL-C-5105 and Amphenol 97 Series styles, and as meeting class IP67 protection against water and dust in the mated condition. The connectors feature a main joint gasket between the plug and receptacle shells that is intended to provide moisture-sealing qualities. The DL Series connectors have aluminum shells and solder contacts, both manufactured to MIL-C-5105 styles and arrangements. Standard shell plating is conductive black zinc alloy; optional green zinc plating is also available. They are available with a choice of 3102A box mount, 3106 straight plug, and 3108A 90-degree plug-shell style in a select number of insert arrangements. Prices begin around $5 each in quantities of 500 pieces.