Having been on the holding end of many a rectal thermometer, it helps to have one that is fast. There's only so long that you can get an animal to hold still while you take his temperature.

Pros: fast

Cons: none

I love the big easy to read screen. (No magnifying glass needed )It reminds me what the last reading was.Most importantly it shuts off itself, because I sure never remember!

Pros: a must have for pet owners

Cons: some animals object

These are a huge improvement over the old thermometers! You get a reading almost instantly which can be very important if you have a horse that doesn't like having their temp taken. The digital numbers are easy to read. One of the first things a vet will do when you call about a sick horse is ask if you took their temp. So this is a must have for your first aid kit!

Pros: Very fast

Cons: None

I manage a large herd, so we're constantly taking temps. This is great for the horses that resent the procedure. Who wants to spend a minute or more at the back end of a dancing horse? The minutes add up, too. Sometimes it feels like half a day wasted in temperature taking. The nine second is the way to go.

Pros: easy to use

Cons: easily broken

The faster the better considering where you have to put it. My vet highly recommended this as a must have in anyone's first aid kit. Your horse will appreciate it too.

Pros: My vet recommended

Cons: None