The UJ/UC and UQJ products are tested at 1550nm during their qualification process. This wavelength is the mid-point of the ‘C’ band (1530nm to 1565nm), and field experience demonstrates that they are fit for purpose for use in this wavelength range with the fibers qualified for UJ/UC and UQJ applications (please refer to FAQ 3.07 on this topic). If you are planning to use the products outside of this range, we suggest that a question should be submitted via the website so that the advice of the UJ Consortium experts can be sought.