Zone info
.PRO stands for "Professionals." and is a so-called generic Top-Level-Domain (gTLD)
Zone use
For persons or entities which provide professional services admitted to or licensed by a government certification body or jurisdictional licensing entity recognized by a governmental body that regularly verifies the accuracy of its data.
Name restrictions
Minimal number of letters: 4
Maximum number of letters: 63
Allowed letters: a-z, 0-9, -
Other restrictions
Please see domain registration