The maker's brass label describes Carters' business as Invalid and Surgical Furniture Manufacturers and gives the address as New Cavendish Street. The first record we have found of John Carter's business is in 1870 with an advert he placed for his Patent Reading Easel. His address is given as 55 Mortimer Street, 5 doors from Great Portland Street. By December 1872 he had moved to 6A New Cavendish St., Portland Place, London. The business kept this address for the majority of their existence, only moving to 65 Wigmore Street in the middle of the 20th Century. The Patent Reading Easel launched Carter's business and its popularity probably led him to investigate further patent adjustable furniture. This was a growing area at the end of the 19th century, with the term invalid also used for furniture that offered a greater comfort. A number of other makers such as Alderman, Ward, Leverson and of course Robinson's were making similar furniture that offered the user a greater deal of comfort. It had a wide appeal.
In 1899 John Carter amalgamated with Alfred Carter of 47 Holborn Viaduct, a competitor who he had taken to court 6 years previously to restrain him from copying his trademarks, copyrights, illustrations and adverts. The name changed to just Carters and they prospered expanding their premises by 1915, to incorporate 125 to 129 Great Portland Street and 2 and 4 New Cavendish Street. Their works were at 15 to 37 High Street, Campden town. Carter advertised extensively and pointed out that 'Wounded Soldiers will derive untold comfort and aid to recovery from the use of Carters' Appliances'. Their range of furniture also increased, selling Bath Chairs, Self-Propelling Chairs, Spinal Couches, Ambulances, Bed Rests, Carrying Chairs and their Reading Easels. Carters continued well into the 20th century with their adverts placed as late as 1958.