diff --git a/pyplayready/device.py b/pyplayready/device.py
index 58d71be..46ffd65 100644
--- a/pyplayready/device.py
+++ b/pyplayready/device.py
@@ -102,4 +102,4 @@ class Device:
 
     def get_name(self):
         name = f"{self.group_certificate.get_name()}_sl{self.group_certificate.get_security_level()}"
-        return ''.join(char for char in name if (char.isalpha() or char in ['_', '-', ' '])).strip().lower().replace(" ", "_")
+        return ''.join(char for char in name if (char.isalnum() or char in '_- ')).strip().lower().replace(" ", "_")