Speedlite 600EX-RT Key Features

  • New wireless multiple flash system using radio wave communication
  • Zoom flash head covers wide range of 20-200mm; Max. Guide No. 197 ft./60m at ISO 100
  • Redesigned contact construction, improved flash head durability, and exceptional dust and weather resistance
  • 18 Custom and 3 Personal Functions for creative flexibility
Speedlite Transmitter ST-E3-RT Key Features

  • Newly designed wireless system uses 2-way radio wave communication for enhanced communication among master and slave units
  • Achieves a transmission distance of up to 98.4 ft. / 30m, all at a 360 degree angle
  • Up to 5 groups, or 15 individual flashes can be controlled via 1 transmitter
  • Supports E-TTL II flash, manual flash, stroboscopic and external flash metering

Maybe this explains why Pocket Wizards new trigger is so cheap.