Aeron(R) Chair Highly Adjustable Model with Graphite Frame Tuxedo Blue Black with Lumbar Support Size C High, wide, contoured back takes weight off the lower spine Wide, soft armrests are sloped in the front for comfort Waterfall edge on seat front reduces pressure under thighs to promote proper circulation The backrest and seat pan move in proper relation for correct support in all postures The Aeron chair by Herman Miller is, simply put, the best ergonomic chair you can buy.