Invisible "Black Flash" Flash Extender Question

[TheLBLman]

I have the Uway "Black Flash" flash extenders.

Has anyone else using these figured out an easy and QUICK way of determining if they're actually working?

Yes, I know there is an "on/off" switch.
But unlike the "red or low-glow" infrareds, I can't "see" if these are working. There is also an issue of checking remaining battery life. Without any kind of battery level meter built-in, is there any other way other than totally removing the batteries, then checking those batteries with a portable battery checker?

 

[BSK]

I have the Uway "Black Flash" flash extenders.

Has anyone else using these figured out an easy and QUICK way of determining if they're actually working?

Yes, I know there is an "on/off" switch.
But unlike the "red or low-glow" infrareds, I can't "see" if these are working. There is also an issue of checking remaining battery life. Without any kind of battery level meter built-in, is there any other way other than totally removing the batteries, then checking those batteries with a portable battery checker?

Watch them with a digital video camera. Digital video cameras' CCDs will pick up some infra-red light. If the flash extender is flashing, you will see it flash through a digital camera's screen viewer.

 

[TheLBLman]

Wow! Did not know that.
Learn something new every day!
Thanks!