window balances

Those stamps just tell us the strength of the balance. Are the balances stamped 1530 have metal channels that are 16" long? Do not include the fittings on both ends in this measurement. If so, see either our S380-16 or S385-16. The only difference between these two balance Series is the depth of the bottom nylon shoe, or the 'heel-to-toe' measurement, so compare both with your old hardware to see what matches best. See the picture below for reference. For the stamp option in either case, choose 1530. 

For the balances stamped 2130, once again confirm the metal channel length. It should be 22". If accurate, then see either the S380-22 or S385-22, pending that shoe depth. Choose a stamp option of 2130.