Meet the SwiftCam M3L: a handy image stabilization system for smartphones. Picking up where the SwiftCam M3 left off, the SwiftCam M3L provides you with an even more stable footage. It has a tripod/extension pole adapter below the grip to make your life easier. It has an adjustable clip that accommodates most smartphones on the market. The device has a battery low indicator and a 1800 mAh battery.
The SwiftCam M3L has a lightweight, strong aluminum body with a built-in 3-axis gyro system to offer you a smooth footage when you are walking, cycling, or skateboarding. Its durable brushless motors provide you with a responsive experience. Not super cheap, but it could improve the quality of your iPhone videos significantly.[Source]