These Longi PV-LR5-01 solar connectors are to be used for making solar panel extension wires for Longi or other solar panels which come with PV-LR5-01 connector leads from the junction box. Spec sheet linked below.

Rated Current: 30A
Rated Voltage: 1500V
Contact Resistance: ≤0.5mΩ
Wire Type: 4mm2 (12 AWG)
Degree of protection mated: IP68
Degree of protection, unmated: IP2X
Safety Class: II
Ambient Temperature Range: -40C / +85C

Documents:
Longi Solar Connector PV-LR5-01 Spec Sheet