I use my SEN-tags on hand-luggage only, so I cannot specifically comment on their durability. However I use my FTL-tags on my checked luggage for more than a year now, and so far it has never gone lost. I like the fact that they just have a number on them instead of an adress but yet make your luggage easily trackable.

And those FTL-tags seem more vulnerable than the SEN ones, if you ask me...so you should not expect too much trouble using them as well.

Greetings - Dirk