I'm tied-up with my own problems right now.
I don't know anybody that makes them looking like that anymore, they're all
encapsulated now, so when they blow-up, the pieces stay together.
What you're looking for a transient voltage suppressor, or surge suppressor.
Google them.
All it does is prevent a big voltage spike from the power line to the device, apparently
a heater in your case. when power is first applied to the equipment.
You look for the device on Google, find out who makes them, used to be mostly
GE, but Matsushita (Panasonic) and a few other companies are big into them now.
Then find the voltage range you need.
REMEMBER, these devices are designed for the PEAK volttage applied to the circuit,
Not the RMS, or what most voltmeters read in now.
You're trying to keep the input voltage spike from damaging your equipment.
Sorry I can't be more helpful, but I gotta go, ....