This is a vintage, later 20th century, modular sectional sofa from the 1970's done in dark a green upholstery by Charlton & Co. It has various pieces which can be placed in different configurations. These are referred to as 'playpen' sofas and they were quite popular in homes in the 2nd half of the 20th century. Some of the leading designers of the playpen sectional were Milo Baughman, Harvey Probber, and Tommi Parzinger. The estimate is based on actual recent past recorded auction sales of comparables. Retail 'asking prices' can be higher and vary.