Hi Jim, good to hear from you again. It must be at least 2 to 3 years.

As far as an answer to your question regarding NCV's, all I can tell you is I've had similiar experiences as the other answers you received and that is they apparently come in all different colors. As a last resource, you might consult with teh chip manufacture representive. Then just before you start to put them in play, send me a set for final approval.