PL95- Prodigy Series gas-lift swivel chairs- feature a comfortable, ergonomically designed and contoured polypropylene shell with an anti-static additive that offers upper back and lumbar support with lateral fl exibility that accommodates different body types. he enhanced waterfall front edge of the seat relieves pressure points and supports students in the upright, forward and lecture body positions. Chairs are available with seat sizes of A offering over 30% more surface area than the industry standard A-size shell and A-size.