The Deskalator sits on your existing desk and lets you change height to suit your posture. Change as required during the day. Scissor structure with gas spring features smooth height adjustment. Original top 890mm wide 590MM deep model FEHARISDKL89BK with additional oversize top. New additional top size Width 1050 x 700. made of scratch resistant surface laminated plywood (I needed a larger desktop space) Currently setup with the larger top. Used for around 9 months and in extremely good condition. Selling both Deskalator and additional top in the one package Original price of Deskalor only was $546.25 inc GST. Price of additional desktop was not cheap but I can't remember how much