It is very easy to mount the arm rests to your chair.
Comfort Move: slide the metal end piece in the sleeve under the seat, and tighten with the knob.
All other models: mount a connection piece on the mechanism of your chair (when the stool is ordered with armrests the connection piece is already mounted), slide the metal end piece in the sleeves under the seat, and tighten with the knob.
First let's check what type of seat you currently have. If you look at the backside of the seat, you will find a gold-colored sticker with technical information. There you'll find a serial number. If this number contains a B, you have the wide seat. If this number contains an S you have the narrow seat. If your chair has the B seat (wide), we can exchange it for you (contact our customer service). If you have the S version (narrow), we do not have a smaller seat, but perhaps a different model would be a good solution for a better fit (for instance the ErgoSolex).
The solution is to exchange your current gas cylinder for a higher one. Please measure your current gas cylinder. Contact our customer service via the "Service and Repair" form to request a new cylinder that is one size taller than your current gas cylinder. On this same 'Service and Repair' form you can also find a link where you can download the instruction on how to exchange the gas cylinders.