Here is the text from Lange website :
"In its anniversary year 2019, the manufactory salutes this exceptional timepiece with the white-gold “25th Anniversary” edition – limited to 250 watches. The collection of ten different models, which will be launched consecutively in the course of the year, is dedicated to the key milestones of the LANGE 1 timepiece family. The hallmarks that all models of the edition share are an argenté-coloured dial in solid silver with printed deep-blue numerals and hour markers, blue date numerals, and a colour-coordinated blue alligator leather strap with a grey seam. The engraved hinged cuvette in solid white gold is another characteristic feature. Its engraving depicts the Lange Headquarters that date back to 1873, the names of Walter Lange and Günter Blümlein, and a relief engraving of the inscription “25 YEARS LANGE 1”.