I bought this to replace a Hubbell switch on a Craftsman 150 PSI air compressor. Here is how it went. All the plumbing fittings worked with zero problems even the unloader line. So, it is 100% compatible on the piping. On the electrical side it required a little work. The Hubbell switch had spade connectors whereas this switch uses screws. So, you have to replace the spades on the wire ends with screw lugs to connect it. The old switch had slots where the wire grommets for the cords slide in. This switch has full round holes and it takes some work to get the power cord in on one side, but it does fit. On the motor side the Hubbell switch had a smaller grommet, but the new switch comes with rubber grommets that can be easily modified to hold the motor cable safely in place and keep insects out of the switch.The Hubble switch was a single pole switch so when the contacts burned up it was done. To my surprise this is actually a 2-pole switch with 2 sets of contacts. I only used one pole and wired it like the single pole switch I was replacing. That means though, when that set of points wears out one could move the wires over to the other set and extend the life!So now we shall see how long it lasts. I was aware it might not be a 100% drop-in replacement, but I wanted to try something different because I was disappointed with the lifespan of the original switch. This one required a very slight adjustment to make it cut off at 150 PSI but overall, it looks to be well made.