A tab on the left spring carrier fits into a hole in the blade at position 4 which restrains the left spring carrier. This allows reverse force on the thumb stud to increase tension in the main spring before the upper restraining pin releases and the blade and carrier can return to the closed position.

The small restraining pin at 3 is the only thing holding the blade open and is prone to failure if abused. The whole slide assembly moves only a short distance, exactly as far as the thumb stud moves. The force that causes the blade to