Used a handful of times. We're upgrading to the hero 7 so won't need this. It's amazing for action shots and can be attached to a chestie or just held. https://shop.gopro.com/International/accessories-2/karma-grip/AGIMB-004-master.html?yoReviewsPage=21
Buy with the GoPro hero 5 black for $500 (selling separately for $250).