Reese 16K Slider hitch

[mstreeter]

I recently bought a Reese 16K tube slider hitch and had it installed.
One question I have is: How do you lock down the reciever plate so that it doesn't swivel up and down from side to side. I know the up and down motion is important when traveling forward and backward but when going down the road I want my unit not to lean right or left and it seems this would allow way too much of that.
On my old hitch there was a mechanism that allowed the hitch plate to move up and down on each side when parking the unit on uneven sites but I could lock it down when I was hooked up and ready to travel down the road.

Thanks for any assistance
MIke