Amazon.com: Synergy Digital Camera Battery, Works with Nikon D7100 Digital Camera, (Li-Ion, 7.0V, 2100 mAh) Ultra Hi-Capacity, Compatible with Nikon EN-EL15 Battery : Electronics
Amazon.com: Nikon EN-EL15c Rechargeable Li-ion Battery for Compatible DSLR and Mirrorless Cameras (Genuine Accessory) : Electronics
Amazon.com : Pixel MB-D14 Battery Grip for Nikon D600/D610 Camera Body Compatible with 1PC EN-EL15 or 6pcs AA/LR6 Battery (Battery Not Included) : Digital Camera Battery Grips : Electronics
Amazon.com : Battery and Charger Kit for Nikon D7100, D7200 Digital SLR Camera Includes Vertical Battery Grip + Qty 2 Replacement EN-EL15 Batteries + Rapid AC/DC Charger : Electronics
Amazon.com: Kastar BG-2N Battery Grip for Nikon MB-D15 work with Nikon D7100 Digital SLR Camera, Proffessional Multi-Power Vertical Shooting Battery Grip [Power Sources: 1 or 2 battery packs EN-EL15, 6 AA/LR6 batteries] :
Amazon.com : Nikon D7100 24.1 MP DX-Format CMOS Digital SLR with 18-140mm f/3.5-5.6G ED VR Auto Focus-S DX NIKKOR Zoom Lens : Slr Digital Cameras : Electronics