27 4 KU CMC 3 channel balances

Depending on the bottom attachment, this is a Series 351 or Series 390 channel balance. Measure up and choose one. Series 351 has the thinner 1" shoe, and Series 391 has the thicker 1-1/8" shoe:

Your balance length will be 28" and you will want to consider a 2740 stamp option for window sashes weighing between 19 and 26 pounds. Weigh the sash if you're unsure.

The S351-28 2740 holds 19 to 26 pounds, so it's perfect for your 23 pound sash. You don't really need to question it any further than that, but here's some more info, if you're curious.

Basically, the "27" is correlated to the height of the piece of glass that shows through the sash, and the "40" means that you need not the 1st-, 2nd-, or 3rd-weakest spring, but rather, the 4th-weakest. Let me know if anything else comes up!

The price is available on our site, and we offer "overnight" shipping which arrives in a single business day. You can check delivery dates and prices online.