On left leg this is the positive air chamber with recommended pressure 120psi. This is a negative air chamber, which is used to adjust the soft or hardness. Add positive gas first, then add negative gas The greater the negative air pressure, the softer the fork Negative air chamber should not be greater than 40 psi.Mexican customers, If you want to receive the package more quickly, and your city is not in a remote area, it is recommended that you choose the Dhl logistics method. About the packaging method You can leave a message telling us the packaging style you need. Otherwise we will be random.