BASI Systems Sitting Box | Pilates AccessoryBASI Systems Sitting Box The BASI Systems Sitting Box expands the repertoire of your BASI Systems Reformer, delivering greater exercise variety and elevated comfort in every session. Its orthopedic padded cushioning supports a wide range of seated, supine, and prone exercises making it an essential accessory for both home practitioners and professional studios. Upholstered in antibacterial, hospital grade vinyl, the Sitting Box is engineered to