RCAI® Standard Knee Immobilizer. 15″ Long (fits 16″ – 22″). RCAI® Knee Immobilizer Constructed of breathable, washable wicking material that “wicks” away moisture from the skin. The movable tri-panel design to accommodate multiple circumference sizes. The posterior aspect of the splint is uniquely tailored for a more custom anatomical fit. Lightweight aluminum posterior medial and lateral stays. Fits left or right. Sizing: Measure mid-thigh circumference. UOM: 1/EA.