Ring terminal for 10 AWG — 5/16 stud, PEEK insulation
The 1577649-1: The circular terminal uses a nickel-plated copper contact with serrated termination, and the PEEK insulation accommodates wire insulation diameters from 0.102" to 0.214" (2.59 mm to 5.44 mm).
Stud size selection across the PIDG, Strato-Therm family
Within the same PIDG, Strato-Therm series, the 1577649-1 uses a 5/16 stud, while the 1577647-1 uses a 10 stud and the 1577641-1 uses a 1/4 stud — the stud size is the primary selection axis for panel hole fit. The 1577649-1 and 1577647-1 both accept 10 AWG wire; the 1577641-1 and 1577640-1 accept 12-14 AWG, so wire gauge narrows the choice before stud size.