One size. SERIO BACK PROTECTOR Is the newest back protection model designed to accommodate a neck brace, as the rear is formed to accommodate the brace. The Serio features an ergonomic design that follows tha natural shape of the rider's back, and features a removable bottom plate to accommodate riders with shorter torsos. The Serio is complete in D30 material in the vertebrae protection column, wich hardens instantly to absorb the shock form impact. Elastic band closure with double velcro adjustments, preformed Pe padding, back padding consists of two parts, one of which is removable and washalbe, EN 1621-2/3 certified