The 1217378-2 is a Mark III 250 Series positive lock receptacle terminal designed for secure, reliable electrical connections in automotive and industrial applications. This terminal accommodates 22-18 AWG wire with an insulation diameter range of 0.060-0.110 inches (1.52-2.79 mm) and features tin-plated brass construction for enhanced corrosion resistance and conductivity. The receptacle employs a positive locking mechanism that securely engages with mating tabs containing holes, with a stock thickness of 0.013 inches (0.33 mm) and tab size of 0.032 inches (0.81 mm). The terminal incorporates reduced insertion force technology and a snap-action confirmation that alerts assemblers to proper mating, while the integral depressor allows for safe removal only when deliberately deflected. This design enhances safety by preventing accidental disconnection and exposure of live parts, making it ideal for under-dashboard installations, recessed switch applications, and other hard-to-reach areas where secure retention is critical.