Accompanied by Uhrenmuseum Glashütte Certificat and one copy from the registers confirming the sale of the present watch to Fa. Dürrstein in Dresden, founder of Uhrenfabrik Union and retailer of A. Lange & Söhne watches, on 31 January 1891 for the amount of 408 Marks. Furthermore delivered with a later A. Lange & Söhne presentation box and later certificate.
The designation Ankerchronometer (lever chronometer) appears in A. Lange & Söhne books around 1882, starting with serial number 12434.
The particularity of these watches is the extremely large balance resulting in more precise timekeeping corresponding to the rates required for a chronometer, thus the name. For an additional sum (25 Marks in the beginning) the watches would be submitted for trial at the Observatories in Leipzig or in Hamburg and could obtain a rating certificate.