Details:
Anderson SB50™ with #6AWG Contacts - Grey (10 Pack) Rated to 50Amps continuous use Voltage Rating: 600V; Contacts will accept wire from 6 to 16 AWG (1.3 - 13.3 sq mm). Remember: Only plugs of the same colour plug together. (Red-Red, Grey-Grey etc).
Link to Anderson Power Products for SB50™ Datasheet
Anderson SB50™ Grey Gray 6319