 "GoPro Surfboard Mounts (GoPro Official Mount)" "Camera & Photo Accessories - Page 311 | All Tech Toys"
"Mount your GoPro to surfboards, kayaks, SUPs, boat decks or other gear where maximum holding strength is needed. Includes an FCS compatible male plug to mount your GoPro using an FCS center fin socket." 
 "GoPro Dual - battery charger USB" " GoPro USB AHBBP301 Digital Camera Accessories CDWG.com
"Conveniently charge two GoPro Li-ion batteries simultaneously with the dual battery charger. Featuring USB compatibility, you can power it with most standard USB chargers, the GoPro wall or auto charger or a computer. Dual LED indicator lights display the charging status of both batteries: in process (amber) and fully charged (green)." 