All-in-one learning pen with optical identification (OID) of hidden code
All-in-one learning pen with optical identification (OID) of hidden code
- CN 2,779,492 Y
- Filed: 12/09/2004
- Issued: 05/10/2006
- Est. Priority Date: 12/09/2004
- Status: Active Grant
- EN CH
-
- Pin
