Amazon.com : AODELAN Flash Trigger Transmitter and Receiver with Universal Hot Shoe for Canon, Nikon, Olympus, Panasonic, Pentax, Fuji, Samsung, Sony : Electronics
Pentax Image Transmitter II - ProductPage
Flashpoint R2 Mark II TTL Transmitter for Pentax Cameras (X2T-P) FP-RR-R2-T-P-II
Elinchrom EL-Skyport Transmitter Pro for Pentax EL19336 B&H
Amazon.com : Neewer 16 Channels Wireless Radio Flash Speedlite Studio Trigger Set, Including (1) Transmitter and (2) Receivers, Fit for Canon Nikon Pentax Olympus Panasonic DSLR Cameras (CT-16) : Electronics