Most amps require a latching style footswitch. The non-latching are for (typically) keyboard sustain pedals and the like. However, the Behringer line of amps with digital effects use a non-latching style, so it is not always cut-and-dry. Basically, the difference is the same as the difference between a switch on a floor pedal effect (e.g. MXR effect pedal) which is latching and a button on a game controller which is non-latching or momentary. I hope this helps you in your quest for "tone."
Scott
"...and I am outta here!"
Scott
Guitars:
Dean EVO Exotic Burl, EVO Special, Vendetta 1000 FR, Stagg Les Paul copy, Squier Standard Telecaster, Squier MIK Stratocaster
Amps:
Fender Princeton 65 (solid state), Vox AD15VT, Peavey Windsor Studio, Crate Vintage Club 50 2x12
Pedals:
DOD FX40B (x2), FX50, FX52, FX55, FX65, FX67, FX80
Washburn LSESLD, LSBOD
BBE Free Fuzz
Behringer EM300, VP1, PH9
Dunlop GCB-95
ProCo Rat II "The Rat"
DigiTech Bad Monkey, RP90
Rockman Soloist
and many, many, many more!