Not only momentary.Make sure you check the constant amp rating too.I just went thru this on my motorhome starting battery. I had 2 fail after a few years,found out that the switches I was using was rated at 250 momentary,but only 20 amps constant. I never checked, meaning what the alternator amp out put is. Mine is 145.So I bought a 180 amp constant.Just a thought.