Originally Posted by Cornish_Celt

if the same numbers are checked more than once they will come up as invalid.

But lets also be realistic here, numbers or black light don't mean shit, anyone can put numbers on a vial or a packet of tabs, underground labs do it all the time to make themselves look more proffessional.(just because it has serial numbers does not mean that the gear inside is real!!)

GBN is an excellent source so nothing to worry about there.

Don't be fooled into thinking that something is legit just because it has serial numbers that can be checked online, anyone could set that up!!

Just make sure you get your gear from a legit source.