RC4WD 4200XL models and nomenclature?

[Northern Farmer]

Four valve block on the 1.5 version
"4-way reversing valve, the use of standard servo drive, a total of 4 road, one on the right side all the way to control the oil, under normal circumstances the oil flows back to the fuel tank directly, producing action after valve is closed, the hydraulic oil flow to the high pressure oil. The actual use only three road"

http://www.aliexpress.com/item/Rc-ca...a-5a821f4c27f8

http://store.rc4wd.com/Hydraulic-Val...15_p_1832.html