We are Lianyungang Huayun Structural Materials Co.,Ltd China. We manufacture The Walk Thru Frame Scaffolding for many years. The Adjustable U-Head Jack we supplied with many specification such as the length 500mm 600mm 780mm and so on. By the way other specifications are acailable at the customer's request. If you have any demand or questions you can contact us freely. Your contacting will be appreciated. We look forward to cooperating with you.