Is this Shoe Depth a Series 385?

Thanks for writing in. Yes, you're measuring the 'heel-to-toe' correctly. If your old balance's nylon shoe is 1-3/32" deep, then you do indeed need the Series 385. Confirm the metal channel length, not including the nylon fittings on either end, for both sets of balances. The balances stamped 3240 should be 33" long, which means you need the S385-33; the balances stamped 2090 should be 32" long. Keep in mind, however, that the balances stamped 2090 use an older rating system we do not go by. To know what stamp option to select, weigh your window sash. You can then match that exact weight with one of the weight ranges listed alongside each stamp option on the product page.