This is my third breed of these holders. It is the most flexible in terms of size as it fits both an iPad tablet and a phone. I mount it on a mic stand so I can read chord charts while playing in a church band. It's the best I've found so far, while others I've used in the past are limited to just one tablet size.
Innovative Car Tablet Headrest Holder: Adjustable Mount for iPad Pro/Air/Mini, Samsung Tablet, Fire Tablets, Phones (5"-13") - Black
11 Review
π Universal Car Headrest Tablet Mount Holder - Compatible with iPad Pro 12.9/11, Phones/Tablets/Switch 4.7"-12.9" - Adjustable Headrest Posts Width 5.2in-5.7in - Sleek Black Design
10 Review
π± Ultimate Tablet Car Mount: Sturdy Gooseneck Flex Truck Holder for Apple iPad (7-13'') with Anti-Vibration Swivel Cradle - Ideal for iPad Pro 12.9, 11, 10.5, 9.7, Air, Mini Tablets (with/without case)
9 Review
Headrest Moonooda Universal Backseat Compatible
11 Review