1,for lift up bed 2, length 61/120/150cm or customized 3, ... is used for Lift Up storage bed which is designed to take most of the weight and to move up and down smoothly . ... the position and dimension of holes can be made accroding to customer's drawing3, pressure of gas spring can be ... chosed by customer, from 20kgs to 120kgs, fit for single, double , queen or king size ...