The 2nd Wadsworth Articulator can be classified as a semi-adjustable instrument. Its basic features include adjustable condylar guides, adjustable intercondylar distance, and an incisal guide that provides a horizontal protrusive table with adjustable lateral wings.
Wadsworth made two significant contributions: a "centering plate," which, when dividers were used to measure the distance from the incisor point (of the mounted occlusal rims) to each individual condyle, determined the "Wadsworth triangle" and the "basic" or compensating curve of occlusion.
In the 3rd model with facebow, the "T-attachment" added a new dimension to facebows by providing a "third point of reference" indicator to determine the vertical position of the occlusal plane.
Dr. Edgar N. Starcke's articles in the Journal of Prosthodontics have more information on the history of articulators.