Neutral density filter set (3 filters,in a 1cm cuvette frame) are the following: filter cuvette 1 : T%=10%, Abs(or Opitcal Denstiy)=1 filter cuvette 2 : T%=20%, Abs(or Opitcal Denstiy)=0.7 filter cuvette 3 : T%=30%, Abs(or Opitcal Denstiy)=0.5 It fits all standard UV-VIS spectrophotometers (such as Shimadzu, Perkin Elmer, GE, HP, and Beckman etc.). These cuvettes are designed for UV-VIS-NIR applications.