A backrest for a scuba diver comprising a shaped plate supporting at least one air cylinder, at least a first strap comprising an upper right portion configured to fit around the scuba diver's right shoulder, an upper left portion configured to fit around the scuba diver's left shoulder and a lower portion configured to fit around the scuba diver's abdomen, wherein the shaped plate has a first right slide-through element and a first left slide-through element adapted to connect the upper right portion and the upper left portion, respectively, to the lower portion of the first strap, at least one weight pocket constrained to the lower portion of the first strap, wherein there is provided an anti-torsion means connecting the at least one weight pocket to the shaped plate and configured to oppose the torsion of the first strap in proximity to at least one of the first slide-through elements.