Review on Zerostart 3400017 Electric Heat Magnet Heater for Transmissions, Oil Pans & Small Engines | CSA Approved | 120V | 200W by Joel Miranda

I put 4 of these on a 100hp tractor engine. The heaters are all working, the temp is now 10 degrees Fahrenheit, 32 degrees 24 hours ago, they've been plugged in for 2 days. The best temperature I've had with an IR thermometer was 23 degrees Fahrenheit on my head just above the heaters. I ordered these knowing an ice storm was coming and thought it would be a quick and easy way to keep my tractor, which I use for the PTO generator, warm enough to start. However, at $200 plus dollars, it's a little better than nothing, but not worth the purchase. Unless you have something really small, they won't work.