This cable is offered for those customers who need to run 4-wire to their control panels. Why four wire vs. three? If you want to be able to run your 120v pumps or any other 120v accessories off the same supply, you need hot L1 (Black), hot L2 (red), Neutral (white) and Ground (green). In a 3 wire setup you only have L1, L2, and Ground so you cannot get 120v.
Specifications:
Size: 10 AWG
Number of Conductors: 4
Conductor Strand: 104/30
Insulation Thickness: 1.14 mm / 0.045 inches
Outside Diameter: 16.64 mm / 0.655 inches
Weight: 0.305 lbs per ft
Current Amps: 25
Color Code:
4 Conductors: Black, White, Red, Green
Good cable at a very fair price. 
