... collapsible side rails. A-12 2012 Two-shake bed with ABS head,central control brake and big or small guardrails Specification: 2150 ... double sided castors of dianeter 150mm with higher stability,ths,it can reduce the friction with the ground and is easier to ... angle is from 0 to 40. 2012 Two-shake bed with ABS head,central control brake and big or small guardrails