DVD packaging differences

[Guest Steve J. Rogers]

I see multiple versions of the same DVD on catolouging sites like guzzlefish.com , same region, same UPC, same price range, same everything (mostly sci-fi genres) with the following added "Checkpoint," "Sensormatic," "Generic," ect Basically it seems something to do with the security tag that is on the discs, don't ask why it seems to only pop up for sci-fi genre specific DVDs and I can't find them for say romantic comedies

 

Can someone please tell me the differences and how I can tell

 

Thanks

 

Steve