Button shape may vary. In some cases, velcro only. 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 using the 3mm hexagon wrench. (Some have no cartridge cover). 2 Turn the CO2 gas cartridge to remove. 3 Undo three buttons on the stand-up collar of the jacket and remove the neck cushion, unfold and spread out. 4 Fully open the fastener across the lower part inside the jacket. 5 Open three fasteners (center and both sides )inside the jacket. 6 Unbutton inside. Unbutton outside of the hip .is buttoned through the loop. 7 Unfasten the Velcro around the "key box" on the right-hand side of the jacket. 8 Unfasten the Velcro at the end of the neck cushion and on the left body cushion. 9 Pull the "key box" downwards to release it from the Velcro. This will allow the neck cushion to emerge gradually. 10 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 Velcro 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 lightly to expose the neck cushion fully along the neck of the jacket. The stand-up collar of the jacket (the "sleeve" for the neck cushion) is to be left open. 5 Fasten . 6 Pull the end of the neck cushion and feed it through the opening on the other side of the collar. The Velcro at the end of the neck cushion is to be attached to the Velcro at the end of the body cushion. Unless the neck cushion is slightly twisted when fed through, the Velcro ends may not mate correctly. 7 Fasten button at the lower center of the neck cushion through the loop attached to the jacket. 8 Fasten buttons to the jacket. 9 Turn the jacket upside down. 10 Fasten outside buttons to the jacket (some are Velcro instead of buttons) 11 Put the folded neck cushion into the stand-up collar. 12 Fasten the center button on the stand-up collar. Put the neck cushion sticking out of the both sides into the stand-up collar and fasten buttons of both sides. 13 Screw a new gas cartridge fully into the bottom until it can go no further. 14 Close the fastener across the lower part inside the jacket. Put on the plastic cartridge cover using the 3mm hexagon wrench. (Some models have no cartridge cover, just the fastener). Caution! 1 To function correctly, the neck cushion must be placed properly inside the stand-up collar. 2 The air cushion must not be rolled up or folded more than once as indicated in the instructions. 3 When installing a gas cartridge in the "key box", make sure the inside is dry and clear of any foreign obstacles. (except the needle inside the "key box" screw) 4 If the gas cartridge is not screwed into the bottom completely, the "Hit Air" may not be activated properly.