These are not cheap copied XT60 plugs. These original Nylon XT60 plugs can handle over 60A current for extended periods without exceeding 80DegC thanks to their better contact surface area. The plug is also less likely to deform or melt in comparison to copied non-Nylon XT60 plugs.
Genuine Nylon high-temp XT60 connectors.
XT = heXTronik.
60 = 60A constant.