Window sash spring identification help please

Question

It is marked "26-4 BA CMC 11". There are 5 windows and since a couple have broken strings I plan to replace all 10 springs.
If I measure tip of metal to tip of metal it is 27" despite the markings.The plastic fittings make tip to tip length of 28"

Bob · Accepted Answer

Thanks for posting. This looks like the S395-27 Channel Balance. For a stamp option choose 2640.