If your chair/Stool is unable to adjust up and down then you may be in need of a new Hydraulic Lift Cylinder. FRNIAMC drafting stool chair gas lift cylinders are more heavy duty than standard chair gas lift cylinders. It is universal size is compatible with damaged or worn out gas lifts on tall task chairs, drafting stools, etc. While this gas cylinder will fit the majority of these types of chairs and stools, it may not fit all. Please remove gas cylinder with care and measure to be sure. Minimal differences in measurements should not alter performance of lift when installed in chair.