Abstract: A lock core includes a lower and an upper lock cover and a lock plate. The upper lock cover has the recessed hollow provided with a plurality of recessed holes respectively fitted therein with at least one steel ball. Thus, when a burglar employs an electric drill to break and unlock a lock by drilling through the keyhole of the lock, the steel balls in the recessed holes can stop the electric drill from drilling forward, having excellent effect of anti-theft.

Abstract: A lock with a fixable key includes a shell, an upper half core, a lower half core, an elastic member and a fixable key. The upper and the lower half core contained in the shell respectively have a lengthwise passageway for a flexible moving member of the key to extend in to unlock the lock. The lower half core has a key hole in a rear end, and a groove for containing the elastic member having an upper end to fit in a notch formed in the groove. The key has the moving member, a push block and a housing having a position recess to engage the upper end of the elastic member so as to position the key in unlocking and make the moving member smoothly slide in the passageway of the lock to prevent the key from deadlocked or breaking in handling in unlocking or locking.