PocketWizard Plus X features:
• Auto-Sensing Transceiver: Easy to use. No settings to make.
• 10 Channels: 1-4 Classic plus 5-10 low-traffic channels
• Backlit Channel Dial: Easy to set channels in the dark
• Internal Antenna: Compact, more rugged design
• Auto-Relay Mode: Trigger remote camera & flashes simultaneously
• Transmit Only Mode: Positive operation in large groups
• Side View Design : Better subject view on camera
• PocketWizard reliability: PocketWizard compatibility
They are now in stock here