Andersen window balance, 11600-3, J1 5#27 3 84

i have a andersen 11600r-2(stamped) with other numbers of J1 5#27 3 84...on the back side it it stamped 11600-3 with stciker of 36x20 single 1/1 lite can you assist on replacement part. the unit mounts with two holes located in the center of the unit