Perpetual Nesting Chair offers a stretch back that molds to every user and a unique, passive ergonomic frame design with independent seat and back flex. This dynamic seating solution automatically responds to you to enhance comfort and continual support. Design features a fully upholstered seat and passive back motion. Instead of including foam, the back is only upholstered with Lycra-based Resilience, a three-dimensional knit with an open-weave pattern for enhanced airflow and a lasting high elasticity. Strong suspension offers increased comfort and durability, adapting to different body shapes and sitting positions. Soft, nonslippery material is multidirectional so it protects clothing from piling and wear. Armless chair nests to 7-1/2" deep. Four casters provide complete mobility. Chair is certified by SCS to be in compliance with specific indoor air quality emission requirements. Meets or exceeds ANSI/BIFMA and ISTA performance standards.