Best Buy: Digipower Multipurpose Battery Charger for GoPro Hero4 Black/Silver & GoPro Hero3+ & Hero Battery Charger Black RF-100GP34
GoPro HERO4, AHDBT-401 Battery (2-Pack) and Triple Charger by Wasabi P – Wasabi Power
Amazon.com: Batmax 3 Packs 1680mAh AHDBT-401 Battery + LED Dual USB Charger with Type C Port for GoPro Hero 4 Black/Silver Action Cameras : Electronics