#1
I want to get a Boss FS-5 to switch on/off the added drive on my amp. My question is, do I get the latching or unlatching? Which would work with my amp?

Cheers.
#2
Latching.
Unlatching means that the button only stays depressed until you remove your foot, this is good for keyboardists for sustain pedals etc.
Latching means that the button stays depressed until you press it again.