Click to view and download the HoverBar Duo Owner's Manual 
What Fits:  

iPad (all generations)
iPad Air (all generations)
iPad Pro (all size & generations)
iPad mini (all generations)

iPhone 12
iPhone 12 Pro
iPhone 12 Pro Max
iPhone 12 Mini
iPhone SE
and all previous generations of iPhone

iPad Clip Maximum Width: 220mm (8.68 inches)
iPad Clip Minimum Height: 127mm (5 inches)

Shelf Clamp Maximum Width: 34mm (1.4 inches)
Shelf Clamp Minimum Width: 10mm (0.4 inches)

Fully extended arm length: 15 inches