Chairs cylinders are sort of a commodity part, similar to casters. Only a few factories make almost all of the task chair gas cylinders in the world. You might be able to find a shorter cylinder that fits your chair on Amazon. your chair proooobably came with a 5"-travel cylinder, and you might be able to find a 3" that fits. The chair maker might even offer one, if they have any sort of real presence/distribution in the US.