I bought a bulk lot of new beam triggers to get what I needed and I have 10 left over.
These are reflective BEAM triggers- meaning there is an invisible light beam shot across the path and bounced back off a 2"x2" reflector. When someone walks through the beam the prop is triggered. IMO these type are the best because they only require wiring to one side of the path.
They will cover up to a 12' path.
They can be affected by fog, but I've been using them with fog without a single issue for two years now. It would have to be REALLY heavy fog apparently to affect them- I use 6-8 gallons indoors in 12 or 13 nights.
These are powered by 110vac and have normally open and normally closed relay contacts rated all the way up to 3A 250vac. So these can be used on more than just simple prop controllers!
They come with easy, no-brainer instructions.
$24.00 each, includes shipping to US! That's what I have in them.
I take Paypal.
PM if you want some.