"Note: Only 1 or 2 spacer blocks on a leg.
Spacer Blocks are 10mm
Legs are: 50mm,60mm,70mm,80mm,90mm,100mm
If they need it to be higher. They need to purchase a higher leg.
They would use this if the vehicle has a curve roof or height Imbalance"
https://www.vehicle-accessories.com.au/index.php?route=product/search&search=spacer