What this means

The IEEE assigned the MA-L block 00D0A1 to OSKAR VIERLING GMBH + CO. KG. Every network interface they manufacture under this block has a MAC address beginning with these digits, followed by a unique per-device identifier. If a device on your network shows a MAC starting 00:D0:A1, it is OSKAR VIERLING GMBH + CO. KG hardware.