Need Coiled Balance Spring

A handy person from San Francisco says:
September 17, 2020
Good morning. I ordered the S170-263, but it was not the right fit for our windows. The attached photo are the two that we need.
Thumbnail of the uploaded file named Coiled Balance Spring - Hotel Carlton.jpg
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Bob from SWISCO responded:
September 22, 2020

Sorry to hear the S170-263 wasn't the right coil spring. Based on these stamps, it looks to me you need instead the S170-407 7 lb spring and S170-409 9 lb spring. However, please note that if these coils are on the same side of the window sash (i.e. one of them is stacked upon the other) then you in fact will need the S171-407 7 lb spring instead of the S170-407. This spring then goes on top of the S170-409. The video below explains more. 
A handy person from San Francisco says:
September 23, 2020
Thank you for the explanation. Can you please also give me the item number and description for the stacked housing for the coil spring?
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Bob from SWISCO responded:
September 28, 2020

Sure, see the 15-156. We also sell the 15-157 drum, which you may also need.
407 Series 170 Coiled Balance Spring
407 Series 170 Coiled Balance Spring
S170-407
$6.55
409 Series 170 Coiled Balance Spring
409 Series 170 Coiled Balance Spring
S170-409
$6.57
407 Series 171 Coiled Balance Spring, Long
407 Series 171 Coiled Balance Spring, Long
S171-407
$6.55
CertainTeed Lance Spring Cover, Wide
CertainTeed Lance Spring Cover, Wide
15-156
$1.97
CertainTeed Balance Drum
CertainTeed Balance Drum
15-157
$1.70
SWISCO S170 and S171 Coil Balance Assembly
SWISCO S170 and S171 Coil Balance Assembly
VIDEO
WATCH >
How to Replace a Triple Coil Balance System
How to Replace a Triple Coil Balance System
VIDEO
WATCH >
Removing a Triple Coil Window Balance
Removing a Triple Coil Window Balance
GUIDE
READ >
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