Frassie Office Gaming Chair Metal Base Replacement With Bottom Plate, Black [Stable metal base] The material of this computer chair base is metal, which is stable. Stable metal material provides a strong chair base. [Heavy duty Bottom plate] Gaming office chair tilt mechanism mounting hole spacing: 10"x6". Turn the handwheel to tighten or loosen the rear tilt tension. [4.9" stroke cylinder] The gas lift cylinder (Class 3) length is 278mm and the extension length is 403mm. Stroke 125mm (4.9inch). [Smooth and quiet rolling casters] This office caster has precision ball bearings to provide smooth and quiet movement, and the steel structure is durable. Universal size: 1122mm. [Service] If there is any problem with the gaming office chair base set, we will solve it for you in time.