A new bike security system, this is what Seat Post Trick Lock offer you. The main goal of this design is to find a way to put some relevant functional objects and combine them together to get better convenience. This concept combines bicycle with bike lock. The lock’s cord is located within the seat post while the dials are located near the top of the seat post. User can detach the post from the main frame in order to access flexible cord, thus making seat post becomes the part of the lock.