Confused about the EPC RFID Tag Classes?

EPC Class	Definition	Programming
Class 0	"Read Only" passive tags	Programmed as part of the semiconductor manufacturing process
*Class 0+	"Write-Once, Read-Many" version of EPC Class 0	Programmed once by the customer then locked
Class 1	"Write-Once, Read-Many" passive tags	Programmed once by the customer then locked
Class 1 – Gen2	"Write-Once, Read-Many" passive tags. UHF Gen2 protocol ratified by EPC Global, Inc. on Dec. 16, 2004	Programmed once by the customer then locked
Class 2	Rewritable passive tags	Can be reprogrammed many times
Class 3	Semi-passive tags
Class 4	Active tags
Class 5	Readers	N/A
* Not an EPCglobal defined class