Need new springs Milguard windows.

Thanks for posting. Does the top fitting look like the 19-005? If so, then I agree this is most likely an S385-33. Just make sure the bottom shoe depth is 1-1/32". See the illustration below for reference. Let me know if your balance's bottom shoe has a different depth measurement.

Comparison of the S378, S380 and S385 balance shoes.

By hook, do you mean the clip at the end of the cord? It appears your balance has a similar clip, though it's a bit hard to see in the photos. So long as the balance otherwise matches up, I think the S385-33, with a 3240 stamp option, is your closest replacement. Please send closer photos of this clip however if you are uncertain. Let me know if you have further questions.