Series 152 coil balance sizing

A quick learner from Northumberland, Pa. says:
The constant-force coil spring that we are looking to replace has an "E" stamped on it, not a weight #. Do you know from that designation what size spring we need?
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Paul Sr. from SWISCO responded:
We need the size and weight of your window sash to figure out the proper spring size. To weight your window sash you will need to remove it from the window and put it on a scale.
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