The 3 turn x 10 Charlynn full hydraulic valve, the 3 turn option for the 10-inch ram size.
A Charlynn valve is what steers a full hydraulic system: you turn the wheel and the valve meters fluid to the ram. If you can't decide between 2 and 3 turn, send us your ram size and tire size and we'll sort it out.
Howe Performance part number 828.