Features:
The YONGNUO speedlite YN-E3-RT II is a for wireless flash . It can control up to 5 groups(15 units) of speedlites that have a multiple flash function using ratio transmission.
Flash Modes: ETTL/M/Multi/GR4/ flash modes. supports 1st curtain, 2nd curtain(Only in M mode), high speed sync.
New designed select dial and display interface for easier operation, supports to set the focal length(ZOOM) of the slave flash.
Firmware can be updated via USB( USB), Built-in assist beam emitter, transmission is 100m.
Two-way 2.4G communication, fully compatible for ST-E3-RT/600EX-RT/YN-E3-RT/YN968EX-RT/YN600EX-RT(II)/YN686EX-RT/YNE3-RX.

Specifications:
Type: On- Speedlite
Exposure Control Syestem: E-TTL II/E-TTL Autoflash, Manual Flash, Stoboscopic Flash, Flash
Frequency: 2405-2475MHZ
Modulation System: Primary Modulation: OQPSK, Secondary Modulation: -SS
Channel: Auto, . 1-15
ID: 0000-9999
Slave Unit Control: Up to 5 Groups(A/B/C/D/E), Up to 15 Units
Transmission Distance: Approx. 100m
Flash Ratio Control: 1:8-1:1-8:1, 1/2-Stop Increments Flash Exposure
FEB: ±3 Stops in 1/3-Increments(When used with flash exposure compensation)
Manual Flash: 1/1-1/128 (1/3-stop increments)
Stroboscopic Flash: Provided(1-500Hz)
Flash Exposure Confirmation: Flash Exposure Confirmation
Model Flash: Fired with ' Depth-of-field preview button.
Linked : Provided
Custom Functions: 9
Assist Beam Emitter: Provided
Firmware Update: Provided
Source: 2 AA/LR6 Alkaline Ni-MH (Not Included)
Flash : Approx. : 10 Continuous Hours
Saving: off After 5 min, of idle Operation
Package Size: 11 * 9 * 7.5cm / 4.3 * 3.5 * 3.0in
Package Weight: 240g / 8.5oz

Packing List:
1 * Speedlite
2 * Shutter Cable(LS-/C1 & LS-/C3)
1 * Storage Bag
1 * User Manual(English & Chinese)