Supco

Supco is the retail brand of Sealed Unit Parts Co., Inc., a New Jersey-based manufacturer and distributor of HVAC, refrigeration, and appliance replacement parts. The brand's catalog is overwhelmingly compressors, capacitors, relays, and other HVAC/R components sold through wholesale plumbing and refrigeration supply houses (Grainger, Ferguson, SupplyHouse, and similar).

A handful of Supco products, notably the Rust Buster line of liquid penetrating oils, are general-purpose enough to have found a second life outside HVAC service work and are sold through Amazon's Automotive category alongside mainstream penetrating oils like PB Blaster and Liquid Wrench. These crossover products are formulated as straightforward petroleum-base penetrating oils for freeing rusted or seized fasteners, the same core use case as any other car-care penetrating oil, even though the brand's primary identity and distribution remain HVAC/appliance-parts trade channels rather than automotive retail.