Idenity of Window balance Requested

Hi,

The attached images show damaged in some areas of the balance but on the side of the balance are the numbers 1820. Also, from one end to the other end of the metal part of the balance is 18 1/2".

I also need another one simular to the above one except on the side of it the numbers 2340 are engraved. Also, from one end of the metal to the other end of this one is 24".


Please let me know what item numbers to buy.

Thank you.