TKSA 51 SKF Alignment Laser – Laser Class 2, 52 x 64 x 50mm. The TKSA 51 shaft alignment tool from SKF provides high measurement flexibility and performance suitability. The TKSA 51 app has been designed to work on a tablet or smartphone and requires no special training. The mobile app includes tutorial videos clearly showing how the TKSA 51 can be operated and how it can provide accurate measurements.