I have been using the ttl trigger from trt-electronics for the last year or so. I probably have around 50 dives with it and have had no problems whatsoever. ttl works great, and i really like the fact the everything is manageable from the camera ( i haven't touched a strobe for as long as i've had it). The on-off switch is very small indeed but i just leave it on all the time. I've probably charged it twice for as long as i've had it, the battery seems to last forever, and it fits in a nauticam housing perfectly. When i first got it, i contacted the manufacturer for some questions and they were extremely helpful so that's a plus. I'll have to agree though that it looks handmade, and the connector to the leds is very thin wire and looks flimsy, but no problems connecting and disconnecting it, which i do after every dive. hope this helps. i've used it in both nauticam and olympus housings with an em5 markii.