Wireless Multi-exposure Intervalometer remote control for Nikon D3400
PRO FLASH + BOX DIFFUSER + REMOTE + CHARGER BATTERIES FOR NIKON D3400 D5600 | eBay
Amazon.com : Vivitar Deluxe Power Battery Grip for Nikon D3400 Bundle with Rechargeable Li-ion Battery, Individual Charger for Nikon, ens Cleaning Pen and Universal Shutter Release Remote Control : Electronics