Kryptonite locks but simple solutions sometimes are the best answer. I am not saying that a lock does not help but this solution is great, hidden and well prefect.
Stemlock integrates two new functions into the bicycle. On one hand, it simplifies storage and transport. On the other hand, it is a powerful protection against theft. Stemlock is the first lock integrated into a multifunctional stem. Using a simple pressure and a quarter turn to the left or to the right, the handlebar is quickly aligned along with the frame and the wheels. With one turn of a key, the handlebar is disassociated from the fork, making the bike absolutely impossible to be ridden or conducted.
IXOW StemLock Classic