Powder Coated Marine Grade Aluminum, Marine Grade Stainless Steel Components & High Strength Composite. 1" Rubber Ball "B" Size. Compatible with most all iPhone and touch products and Samsung galaxy s4. Lifetime warranty. Socket technology allows for multiple adjustment angles and articulation of device. Rubber coated tips will hold device firm and stable. Spring loaded holder expands and contracts for perfect fit of your device. High strength composite and stainless steel construction.