Fasteners to join "Hit Air" and jacket. Fasteners to join the neck cushion and jacket. To prepare for removal, spend a few moments to study the procedures and follow the instructions carefully. Study will also assist with replacement - it's just the reverse of removal. It's really quite simple! 1 Remove the plastic cartridge cover on the upper side of the "key box" attached to the jacket by using the 3mm hexagon wrench. (Some have no cartridge cover). 2 Turn the CO2 gas cartridge around to take out. 3 Undo three button and Velcro around the neck. 4 Fully open the fastener across the lower part inside the jacket. 5 Open three fasteners (center and both sides ) inside the jacket. 6 Undo fastener at the end of the neck cushion and of the body cushion. 7 Unfasten the Velcro around the "key box" on the right-hand side of the jacket. 8 Pull the "key box" downwards to release it from the Velcro. This will allow the neck cushion to emerge gradually. 9 Pull gently (do not force) and the air cushion will separate from the jacket. 1 Spread the jacket flat on the floor, with the inside up. 2 Fully open the fastener across the lower part of the inside of the jacket. . 3 Place the "key box" into the slit on the right-hand side of the jacket and fasten the Velcro. 4 Hold the fastener at the end of the neck cushion and feed it through the opening above the "key box" (underneath the collar). It must go through the chest side of the armhole and not through the back side of the armhole. Pull gently to expose the neck cushion fully along the neck of the jacket. 5 Fasten 6 Fasten at the end of the neck cushion with on the body cushion. 7 Fasten the Velcro inside the opening (for the neck cushion of the jacket) to the Velcro attached to the neck portion of "Hit Air". Then fasten the Velcro around the neck. 8 Turn the jacket upside down. 9 Do up buttons (around the neck) and (around the hip) to the jacket. (Some models provide Velcro instead of buttons.) 10 Screw a new gas cartridge fully into the bottom until it cannot go any further. 11 Close the fastener across the lower part of the inside the jacket. Put on the plastic cartridge cover using the 3mm hexagon wrench. (Some models have no cartridge cover, just the fastener). 12 Close the fastener across the lower part inside the jacket. Caution! 1 When installing a gas cartridge in the "key box", make sure the inside is dry and clear of any foreign objects. (except the needle inside the ""key box" screw) 2 If the gas cartridge is not screwed into the bottom completely, the "Hit Air" may not be activated properly.