These are temporary czech phone numbers or also called czech numbers. This means that they are only available for a short period of time. Some czech phone numbers last for several months, others only a few days.
Please do not use such a czech number for important text messages such as passwords, private text messages to friends or for phone verification on websites. Anyone could take over your account by reading the text messages of these czech phone numbers.
If you do not live in czech republic and still want to use a particular site or web that only accepts czech users, it is necessary to have a czech phone number to verify your account.
Most websites that require phone number verification have a limit on how often you can use a phone number. In this case it can happen that some of our czech phone numbers are blocked. But this is not a big problem. Just use one of our other czech phone numbers.