2" (50mm) wide x 9" tall main support tube that will fit most standard chair bases
4.5" height adjustment range (up & down)
To raise seat height - hold plastic center bushing while turning seat top counter-clockwise. To lower seat height - turn seat clockwise while holding plastic center bushing. The requirement of holding the plastic center bushing while adjusting keeps the spindle from adjusting seat height while the user is seated.
11" overall length from end to end when fully compressed / retracted
15.5" overall length from end to end when fully extended
Ideal to replace gas cylinders on many standard office chairs, task chairs, executive chairs, and more!