All colour and wire combinations are UL-rated to 600V DC and 175 Ampere. If you have no need to visually indicate the voltage, you can use any colour you like. 

Same-colour housings mate together but not in different colours:

Usage Information: Pick a voltage or use any colour you wish. The connector is 600V rated. Colour can be used to indicate voltage:

You can use every colour housing for up to 600V installations. Housings are colour-coded to avoid misconnecting to other voltages

12V Yellow
18V Orange
24V Red ( very common )
36V Grey ( very common )
48V Blue ( very common )
72V Green
80V Black / or no indication. Mates all colours.

Product information - Anderson SB175

This is the Anderson SB® 175 - 175 Amp Anderson Connector Kit
includes 1x housing and 2 contacts.

This connector type support wire sizes from AWG #6/8 (16mm²) to 1/0 (50 mm²) fit in the second to the largest connector in the SB® series. The 3 pole SB®175 adds an additional position for power or grounding. All Multipole wire connector housings are genderless and mate to themselves minimizing inventory and assembly complexity.

• Silver Plated Wire Contacts up to 1/0 (50 mm²) Allows UL rated currents up to 280 amps
• Chemical Resistant Housing Option Extends temperature range down to -40°C while offering enhanced UV and chemical resistance
• UL Rated for Hot Plugging up to 100 Amps Great for battery or other applications where the ability to interrupt circuits is required

This Product is called usually as SB175, SB 175, 175A connector or Anderson Plug and Heavy Duty Quick Connect Anderson Plug