Standard phone grips are available in either white or black base colors. MagSafe grips are only available in black. Background color is fully customizable.
Applicable on anything with a smooth, hard plastic case. Will not stick to silicone, highly textured surfaces, and many soft cases.
Gel does not stick "as well" with naked iPhones. While it does stick adequately to a naked base model it will not stick "as well" as if you used a suitable case.