The CK20S Does not have a true shuttle.
1st and reverse are opposite of each other and those 2 gears are synchronized.
So if you are doing something in high or low range and you are in 1st you can push in the clutch and pull it into reverse and you will not grind the gears.
But as far as having a true shuttle with every gear having a forward and reverse, this model does not.
You have to move up to a CK25 or switch to a hydro CK20S.
BTI