What's in the Box: 1* office chair base replacement bottom featuring for wheels for criss cross chair, ensuring a unique and stylish upgrade for any office environment; 1* universal gas lift cylinder; 5* Premium casters designed for smooth and quiet operation across all floor types. Universal Size & Safe for All Floors: Equipped with chair wheels, our caster set with a 75 mm diameter can safely glide on your vinyl, almost any kinds of carpet (except thick and tall carpets), hardwood flooring, or tile, protecting your floor from scratches and damage. 120 mm (4.7 in) Adjustable Stroke Length: Includes a desk chair base replacement that allows for a height adjustment from 345 mm (13.6 inches) to 465 mm (18.3 inches), fitting most office chairs in the market. This feature is perfect for optimizing your workspace ergonomics. Extremely Durable Structure and Materials: Our product features computer chair wheels that combine durability with a sleek design, ensuring lon