'Blokken,“ said the boy triumphantly. ”We were right.“
There were only six firms in the world capable of constructing deposit boxes of this quality.
Artemis had hacked their computers and found International Bank on the Blokken client list.
Blokken was a small family company in Vienna that also made boxes for several banks in Geneva and the Cayman Islands. Butler had paid their workshop a little visit and stolen two master keys. Of course, the keys were metal, and would not escape the detector arch, unless for some reason metal had been allowed through.
Artemis reached two fingers into his mouth, dislodging the brace from his upper teeth. Behind the brace itself was a plastic retainer, and clipped to that were two keys. The master keys.
Artemis rotated his jaw for a few seconds.
'That feels better,“ he said. ”I thought I was going to gag.“

The Opal Deception, Chapter 2