Hi,
My name is Tony, I have a small window repair business in the uk. I have recently picked up a job of maintaining a block of apartments that all have coil balances. Some of the coils have already failed and the others are looking in a poor state and I don't like they will last much longer. I would like to replace a lot of the coils and have spares for the future. The markings are from spring up, 7s, 76 & 16. The pivot foot has 550 stamped on it. Hopefully the phots will help you.
Any help would be much appreciated.
Kind regards
Tony