We got these when we bought our in-ear thermometer. I thought it was good because it would be more hygienic but they are tricky to use as they slip off easily. Our son hates having his temperature taken and we often have to wrestle him to take it so these just fall off in the process! We have not bothered using them now, so I wouldn't recommend them - unless you have a very compliant toddler! You can use the thermometer without these just fine!