EVDB56 Electrostatic Discharge ESD chairs are ESD versions of the Discovery Back series of Office Master DB chairs. Designed to support shoulder with a special back design and comfortable memory foam back cushion. Lab Stool version of DB57 with adjustable height foot ring. Seat height 23-33 inch. Office Master?s Double Comfort Seating? (DCS) Technology is a unique layered system of self-conforming memory foam, combined with firmer Office Master high-resilience cushioning.