window balance

I'm not positive, but this looks like the S380-27 with a 2650 stamp option. If you've got a 19-005 top and a 15-005 shoe, then you certainly need Series 380, and you should choose the 27" version to match your measurement. That length makes sense given a stamp of "26 5".

If your shoe doesn't match, you might need the Series 385, which is the other possibility I can think of. That one uses a larger 15-004 shoe, so you can measure the shoe to tell the difference. 15-005 measures 1" front to back, and 15-004 measures 1-3/32". This is the only difference between S385-27 and S380-27.

The last step is to remove your window sash and weigh it. If it weighs between 26 and 30 pounds, you will, in fact, need the 2650 stamp option. If the weight is something else, choose the proper option from the chart on the S380-27 or S385-27 webpage.

S380-27 with a 2650 stamp option should work for you, given the information you provided.