Please read my profile. These are options such as the hsu used with a HERO9. Compatibility with other models is unknown. The arms etc. are probably the same. As for the drawbacks: - The screw adapter is attached crooked. - The clamp adapter for the bar has scratches, and the non-slip material that was attached to this part has been removed (it was actually slippery and not useful). Also, the screw-type attachments have weak holding power, and they can warp or break if over-tightened. Otherwise, the product quality itself is quite good.