Need a 28? replacement balance

Hello, Deepesh. I am confident that we can find a match for this balance, but I cannot identify what you have from this photo. Stamps aren't actually a part number, it just tells us how strong the spring is.

In order to determine the Series, I'll need to see a clear picture of the top nylon fitting. As for the bottom fitting, which is already in your photo, I'd like to know its depth.  

We will be able to recommend a match after I have those two pieces of information.

Thank you for the photos. Your balance closely resembles both out S385-29 and S380-29. The only difference between these two balances is the depth measurement of the bottom balance shoe. The depth measurement of the Series 380 is 1" and for the Series 385 is 1-3/32". Measure the depth of your bottom shoe, like in the diagram below, to determine which balance is the best match. Whichever one chosen will go with the 2840 option. 

Alternate view of 15-004

In your photo, it does look like it could be 1" but we can not always get the best look with a measuring tape next to the part. If you feel the depth of the bottom shoe is 1", then you can go with the Series 380.