Pat, that's too bad about the lockup with the Vello unit. I considered that along with the hähnel, went with the latter for the smaller size of the transmitter (can be concealed in my hand if I'm in the shot, but still bigger than the little Canon RC1 that doesn't work with the 1-series). No problems with the hähnel (the battery issue was obviously a wetware problem), it works reliably. The only annoyances are related to auto-off timeouts – the transmitter shuts off after only 1 minute (adjustable), and the receiver doesn't seem to time out at all (meaning the battery dies in storage, and it's an LR2 not a 'standard' battery).