This Antique Snellen's Standard Test-Types Vision Test Cards appears to have been produced for use by the New York Central System for checking the eyesight of their prospective and current railway employees. Included in this set is the following. The American Railway Association Standard Reading Card. Certificate of Vision, Color Perception, and Hearing (last one on original pad). Each of the cards includes a hole, typically with a grommet in it for hanging at the prescribed distance from the person being examined.The cards are a nice weight card stock. The envelope included is basically just a remnant to help complete the set. I try to respond as quickly as possible, but please allow up to 24 hours for a response. For more of my items available for sale.