This Adjustable Headrest Pillow offers neck support for office chairs and is an essential ergonomic chair accessory. The product has a breathable mesh surface that is easy to clean and can be lifted up and down. The head pillow can also be turned for added comfort. Additionally, it comes with specific installation sizes based on the thickness of the chair bottom, ranging from 1.0cm to 2.8cm. This product is designed to relieve pressure on the cervical vertebrae and may have a slight margin of error due to manual measurement. If there is sponge on the backrest, be sure to measure and consider its thickness before using the included retaining clip for installation. The product is available in black, gray, blue, and green and comes with all necessary screws and fittings. Please note that there may be a 1-2cm difference in size due to manual measurement and slight color variations due to lighting and screen differences. For any inquiries about our product, please contact us for a prompt and satisfactory