Tab width and wire range
The 2-520103-2 is the male 0.250" (6.35mm) tab member of TE's Ultra-Fast quick disconnect series, fully insulated and free-hanging. It accepts 18-22 AWG wire with a crimp termination and a tin-plated brass contact; the insulation diameter accommodates up to 0.135" (3.43mm).
Crossing to a female Utilux tab
The 2-520103-2's 0.250" (6.35mm) tab width and 0.032" (0.81mm) thickness match the Utilux 1-1659250-0 female receptacle, which accepts 17-20 AWG and is non-insulated — the wire gauge overlap is 18-20 AWG, but the insulation diameter of the Utilux part (0.102", 2.59mm) is narrower, so a fully insulated male tab will not seat in the non-insulated female housing without stripping the insulation back.