During 2006 we received NSF Certification for the Thermapen. Nothing was really changed on the Thermapen so if you purchased your unit earlier and it does not bear the NSF mark, youre not really at a disadvantage. Some commercial customers may sometimes require the NSF mark on any products used in the food preparation process. Go here to learn more about the significance of the NSF mark.
http://www.nsf.org/consumer/about_NSF/cert_benefits.asp