There is no difference between the Hakko T15 Series Composite Tips and the older T7 Series Composite Tips.
Hakko is always working to improve product performance, and through proprietary process controls during the production of the tips, we have been able to improve the temperature accuracy of our composite tips.
The part number was changed as part of our globalization effort to have one common tip part number for our composite tips regardless of the country where they are sold.
The improvement in the production of the tip means that the use of the process gate to identify to the station the thermal characteristics of the tip is no longer necessary. Turning off the process gate allows the operator to eliminate the step of identifying the tip to the station through the process gate, saving time and improving productivity.