When combined with a Ray Allen indicator, this sensor can be used to measure the position of wing flaps, cowl flaps or many other mechanisms. (NOTE: Ray Allen T2 and T3 servos have their own built in sensors.) Measuring only 2.7”(69 mm) x .5”(13 mm) x .8”(20 mm) , it's small enough to be installed almost anywhere. It is available in the following travel lengths: .5”(13 mm), .7”(18 mm) and 1.2"(30 mm).