Thanks for posting. These are in fact not Extended-Travel balances, which have metal channels with uneven lengths and pulley systems embedded into the shoe. You instead have standard channel balances. At first glance, this looks like either a Series 380 or Series 385 Channel Balance. The only difference between these two balance Series is the depth of the bottom nylon shoe, or the 'heel-to-toe' measurement. See the illustration below for reference. Measure the depth of your old balance's shoe to determine which matches best. Let me know if the depth is in fact less than either of these choices.
Assuming you have one of the two balance Series I've mentioned, then you'll ultimately need either the S380-24 or S385-24, stamped 2330, and then either the S380-28 or S385-28, with a stamp option of 2730. Let me know if you have further questions.
