My husband was surprised when he went through an airport scanner and kept setting it off.  After taking off everything he could think of that might cause the alarm, he finally left his wallet out of his pocket and could go through without an alarm.  It appears the invisible blocking material blocks what's inside when you try to scan through it.  He likes the wallet itself.  It's well made and holds all the cards and cash he had in his old wallet.  So far he's been very pleased--as long as he remembers to take out of his pocket at the airport scanner.