Brinsea Spot Check Digital Thermometer for Egg Incubator USF135C
Product Review (submitted on May 12, 2013):
The gold standard of small thermometers for hatching. We have three, and they are extremely accurate. They can detect hot spots in a larger, cabinet incubator.
We DID get a defective one, but it was replaced immediately. The tip of the probe is the business end, and will not take ANY abuse at all. It is connected to the body with two micro-fine wires in a plastic tube. Handle the tip carefully. It is the weak point. An all metal probe would be far better.
Our hatching rate increased dramatically when we began using these. You can set all your other thermometers with these, at least we do, and have a 95% hatch rate in a pair of 300 egg incubators.