Wales
Charles Wales from Detroit filled his first patent application for adding machine in September, 1902, and when in 1903 the patent was granted, he decided to establsih a company to manufacture the device. Thus the Wales Adding Machine Co. was founded and soon began production of the remarkable series of adding-listing machines.
In the beginning of 20th century, the adding machines of Wales Adding Machine Co., Wilkes-Barre, Pennsylvania, (together with the Comptometer of Baldwin and Dalton of Hopkins) are a strong competitor of Burroughs.
This success of the innovative Wales machines was due to the advanced construction, "visible" printing device above the keyboard and the variety of models, launched to the market. At one point, more than 40 different models of varying carriage width, number of places and auxiliary keys existed, but in 1923, the line was consolidated into two main classifications—the large machines, and the small portable models.

Wales Adding Machine
The Wales Adding Machine is a full keyboard machine with integrated printer. It is a quite massive device, with dimensions 38 x 50 x 25 cm, and weight 29 kg. The first patent for the machine was granted in 1903. The advertising campaign started in 1908. The 1914 prices started at $175.
The Wales machine was extremely popular in banks and other companies. In 1916 brochures are listed over 2000 banks using Wales machines and 54 companies (not all of them banks) that were using from 5 to 83 each.

Wales Adding Machine, Model 20, schema
During 1920s the machine was sold successfully in two main varieties—large machines and portable models. All the models featured one or two calculating mechanisms. During the calculations, the operator first entered the number from the keyboard, then using the right lever the number is printed and added to the partial sum, and the keys are returned to the initial position. There are additional keys for special operations. The portable machines are a smaller variant of the bigger, featuring almost the same functionality.
The Wales Adding Machine is a quite fancy device, featuring beautiful beveled glass sides. That's why some people call it The "Mac" of Early 20th Century Machines :-)