Concept 2 PM5 Rowing Machine Tablet iPad Samsung XL Holder
 
The bottom holder slides onto the top of the PM5 controller, the top of the holder moves on a steal rod, to secure your device we use a locking bolt to hold the top bracket it position ( meaning it can be placed in any position but doesn't require any tools ). 
 
Both brackets a have rubber inserts to prevent any movement when rowing and any device up to 12.9 inch's can be used.