DidoMall via Amazon offers Prime members the Kupton GoPro 6-in-1 Harness Strap Kit, model no. GP004, for $8.99 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $5.58.) That's $31 off list and the lowest total price we could find. It includes a head belt strap, chest belt strap, two thumbscrews, and j-hook.