26 5 FU CMC 2

Thanks for posting. This looks like either an S380-27 or S385-27 Channel Balance. The only difference between these two balances is the 'depth' of the bottom nylon shoe, or the 'heel-to-toe' measurement. See the diagram below for reference. Measure your old balance's shoe depth to see what matches best. In either case, for a stamp option choose 2650.

Comparison of the S378, S380 and S385 balance shoes.

For removal and replacement instructions, see the video below.