Hi,
The balancer for my window fell out, and there's been a few others that should be like this that are like this in my house. I don't think this matches any of the available ones in the shop.
From what I can see, the only marking on it is 25 3 and BSI RK near the bottom, as shown in the first image. It should be about 25 inches long. Could I get some help with finding a replacement? Thank you!