Standard Contactor, double pole, single throw, (DPST). Most often used for electric heater element switching. Brand names are not really important if your contactor looks like this one. Furnas, Joslyn Clark, Siemens, and Products Unlimited all make this same contactor. What's important is the coil voltage and amp rating that most likely matches yours.
Note that most contactors in use are of the 115 volt coil, 30 amp contact variety. A few exceptions do exist though, noteably, -some- Cal Spas use a 24 volt coil. Please remember if you select 24volt coil it comes in 30amp ONLY
This contactor, in the basic version is EVERYWHERE. From home heating to air conditioning - to spas and hot tubs. It has the ability to power any high current device with a simple coil connection.