For ALL Longarm/Midarm machines. http://www.superiorthreads.com/shop/p... The new electronic Superior Top Tension Pro measures the exact amount of top tension applied by the tension knob. Adjust the top and bobbin tension to achieve the perfect stitch, then measure and record the top tension number using the Top Tension Pro. When you use the same thread combination again, quickly refer to your notes, set the top tension to that number, and you'll be back quilting with the proper tension in no time. This gauge takes the guess work out of adjusting the tension every time you change thread.