[Heathkit] OT, Electric Heater Question

[km1h]

I figure someone here knows the answer! Excuse the O/T subject.

What is that thingie in all heaters in series with the AC line, it looks 
similar to a diode?? Are these things generic, there are no markings and Ive 
seen them in all sorts of heating devices?

Source of replacements?

Is it safe to bypass it if everything else in the circuit checks OK?

I have a heater that I use in the garage to warm my buns when Im working 
down at floor level. It died the other day. I jumpered it and brought the AC 
up with a Variac to 70V and all appears OK, didnt go any higher.

Thanks
Carl/KM1H