Use the following images to determine the version of your Colorimeter.

1995-2000
3403-col-din.jpg
Sensor Booklet for 1995-2000 model:
https://www.vernier.com/files/manuals/col-din.pdf
also see How do I calibrate a COL-DIN Colorimeter using the LabQuest App?

2000-2014
3403-col-bta_2000.jpg
Sensor Booklet for 2000-2014 model:
https://www.vernier.com/files/manuals/col-bta_20141205.pdf

2014-current
3403-col-bta_2014.jpg
Sensor Booklet for current model:
https://www.vernier.com/manuals/col-bta

The Colorimeters with the white BTA connector, available since 2000 will auto-identify when connected to a functional interface. The earlier box-shaped version used a 5-pin DIN connector and did not include the auto-ID feature.

2018 – current

Sensor Booklet for current model:
https://www.vernier.com/manuals/gdx-col