“Custom Select” is Kincaid’s build-to-order upholstery program, which lets you configure the chair in multiple ways (arms, bases, back style, cushion style, upholstery, etc.). The “755-84T” (or “84T”) is a variant where the “T” generally refers to T-front cushion (i.e. the seat cushion has a “T” shape in front) as opposed to a flat front.