Blackburn ADR21SH ADR21 WITH SOCKET HEAD SCREWS

Yes. The ADR21SH is a dual-rated mechanical connector, which means it is rated for use on both aluminum and copper conductors. The body is aluminum with a tin-plated finish, which is what makes the copper connection acceptable by preventing the dissimilar-metal corrosion you would get from bare aluminum on copper. Use an approved joint compound on aluminum runs per normal practice.

One. The ADR21SH is a single-conductor connector, so it lands one wire per connector. If you are tapping or splicing multiple conductors into a common point, you need a multi-conductor mechanical lug or a separate connector for each run rather than doubling wires into this one.

The SH suffix means socket head screws instead of the standard screw head. Functionally it is the same ADR21 connector body, but you drive it with a hex key rather than a slotted or hex-head driver. Electricians pick the socket head version when they want a recessed head in a tight enclosure or want to match the driver already in the kit.

Sold each. One ADR21SH connector per unit, so order one per conductor termination you are making. Distributors stocking for panel or service work generally buy in multiples of the terminations on the job.

The tin plating on the ADR21SH's aluminum body is there to slow oxidation at the contact surface and keep the connection stable over time, which is why dual-rated connectors are specified in service equipment and outdoor gear. It does not by itself make an assembly weatherproof; the enclosure rating still governs. For direct burial or submerged use, specify a connector rated for that condition instead.

Mexico. That is the stated country of origin for the ADR21SH, which matters for institutional and government buyers working to domestic-content or trade-agreement procurement rules.