Manual hoists can be designed in either a chain or wire rope configuration, and are mainly used for occasional lifts where speed of the lift is not a factor. One chain is used to lift and lower the load and the other chain is used to support the load. Endo supplies spring balancer, air balancer in India. Click here to know more. http://www.endo-india.co.in/index.php/product/productsubmenu/46