1 set.
In photo: A=52 factory gearbox. Which have only 1 reverse shift lever. (sorry, please modify your old one.)
B=331 factory gearbox. Which have 2 reverse shift levers. (will be provide a replacement for you.)
1st step: please put on all the linkage parts onto your gearbox!
2nd step: then, ask someone help you, mark the right place of the hand shifter itself onyour tank. Mark sure that's the best place which you can move into all the gears.
3rd step: weld some plates or screws onto your tank! DON'T weld the shifter onto the tank directly!
4th step: now you can install the shifter onto your tank now.