3-521057-2 is an Ultra-Fast Plus fully insulated FASTON tab terminal designed for quick-connect electrical connections. This .250 series terminal accommodates 16-14 AWG wire with an insulation diameter range of 0.090-0.160 inches (2.29-4.06 mm) and features brass base material with tin plating. Key dimensions include A: 0.290 inches (7.37 mm), B: 0.522 inches (13.26 mm), C: 0.230 inches (5.84 mm), and D: 0.855 inches (21.72 mm), with a mating tab size of 0.032 x 0.250 inches (0.81 x 6.35 mm). The terminal features a nylon housing rated UL 94 V-2 for flammability, color-coded blue for 16-14 AWG identification, and is UL rated at +105°C. These terminals are ideal for applications requiring reliable, insulated quick-connect solutions with shock and short hazard prevention.