The 1-87977-1 is a single-row receptacle assembly part of the AMPMODU Interconnection System Mod IV series, featuring an outrigger design with 0.100 x 0.100 inch [2.54 x 2.54 mm] centerline spacing and end-to-end stackable configuration. The housing is constructed from glass-filled thermoplastic rated 94V-0, with dual cantilever contact beams incorporating a built-in anti-overstress feature for reliable matings. Available in multiple position configurations ranging from 6 to 72 positions, with contact plating options including duplex gold and tin finishes on beryllium copper or copper-tin-phosphor bronze contacts. The receptacles mate with 0.025 inch [0.64 mm] square or round posts and support a contact current rating of 3 amperes with termination resistance of 12 milliohms maximum for beryllium copper contacts. These assemblies are ideal for wire-to-board interconnection applications requiring compact, stackable, and reliable connections in electronic equipment.