The Solo Pro Back Pack Carrying System is well padded, adjustable for an individual fit and ensures good ventilation. The wide shoulder and hip straps distribute weight evenly in the same way a good rucksack does. That means you can work longer and feel less tired at the end of a day's spraying. The system fits all Solo back pack sprayers with fill volumes of 10 or 15 litres (Models 425, 435, 473D, 475). Delivery does not include the sprayer itself.