From Therm-O-Disc, this thermal cut-off switch is N/C (normally closed) by definition. (Thermal cut-offs are what keep your coffeepot from burning your house down.) This one shuts down between 221°F (105°C) and 248°F (120°C) and measures 5/8" dia x 9/16" thick, with (2) axial terminals.

It's a nonpolarized bimetal heat sensor, 1/2" long with rubber sleeves and 6" long leads. It's also mysterious, because when used as a thermocouple multimeter input, it reads approx 94° in nearly boiling water but approx 170° in ambient air. Wethinks some sort of inversion or scaling is going on, but a person with your smarts will surely figure it out.

To heat what is anybody's guess, but it's a U-shaped heating element, 8-3/8" x 2-5/8" x 1/4" dia with a 107 Ohm Resistance and rubber grommets above the 3/16" wide power terminals. When CJ heated it up to 120F, those grommets got gooey, so he says use lower voltage DC.

Return with us now to those thrilling days of 1977, which is when this Pyrex-topped heating element was made as part of a stovetop hotplate. Measures 10-3/8” x 5-3/8” x 3/16” thick, and draws 120W at 120VAC with a thermal cutoff, neon indicator lamp, 1.5 ohm power resistors on both legs as fuses, and 4-1/2” leads. Will heat up to at least 230F. Made in the USA by Sierracin/Thermal Systems, part #976-4935-3.

This dipped, nominally 10K Ohm thermistor is on a heatshrunk and tubed 27” lead with a 6mm 2-pin Molex connector. Resistance drops as heat increases (NTC). Comes encased in a 1” x 1-1/8” plastic housing with a clip. AC takeout.