Update: to V.2 [Note: this design is still in alpha and is still being tested] Design:  A rip-off of the design of the hall pass by sparrows, (you know the one) but this one won't get caught in a metal detector by the TSA! Usage:  Bypass the latch of a locked door by inserting the card over the lock, pushing it down using the card hook then simply  pulling the door and the card at the same time. Boom. Done. Open Sesame! Measurement:  standard credit card size (85,60 x 54.95)  with a thickness of 0.12 mm, fits any wallet like a glove. Material:  Recommend using a strong material for this type of project like ABS since it will be needed forcing the latch inwards.  Anyway support the original design, happy pen-testing.