Most padlocks can be opened by inserting a thin piece of metal called a shim between the shackle and the body of the lock. This will need to be done on both sides if there are locking levers on both sides. The shim pushes the locking latch aside and allows the lock to open. High-security padlocks often use a ball-bearing latch, which can not be pushed aside with a shim. Some door locks can be shimmed with a credit card or similar thin plastic object. The card is placed between the door and doorframe, which pushes the latch aside. Combination locks can not be picked, but it is often possible to find the combination by feeling for certain clicks inside the lock, except on certain high-security safe locks. Some combination locks have small cracks through which the parts inside the lock can be seen, allowing the combination to be determined. The Master Lock #175 brass combination lock has a very unique flaw allowing a small piece of metal to be inserted into the bottom of the lock, which pushes the locking bar aside, opening the lock. A special pick exists for disc-detainer locks, but it is only effective on inexpensive locks that do not have false gates. A well-made disc-detainer lock with false gates (such as the Abloy Protec) is considered almost impossible to pick. Lever locks are considered difficult, although possible, to pick and also require a special pick. Tubular locks can be picked with a special tubular pick. Some poorly-made tubular locks can be picked with an ordinary writing pen. Most car locks can be defeated by inserting a metal or plastic rod with a small hook on the end into the area between the rubber seal on the window and the car body, and using the hook to pull the lock lever that is normally pulled by hand from the inside of the car. On most cars, it is possible to electrically connect the switch contacts on the ignition lock to start the car without a key, completely bypassing the mechanical lock. This is called hotwiring the car. Most cars use a wafer-tumbler based lock, so it is also possible to pick the door or ignition locks the traditional way. Some cars, such as many Honda and BMW models, have electronic protection against both hotwiring and traditional picking.