Having trouble identifying a part

A professional from san diego says:
August 4, 2020
Hello,
I have several windows where I need both the housing and the springs. Is the coil always screwed in? and how does it connect to the housing? Where can I purchase these? I need 11 pairs total. I assume both sides only need one coil? The coils in this picture don't have any holes, so I'm kind of confused how it will stay connected to the frame. At the very least a name of the parts or a company that sells the parts.
Thanks
Thumbnail of the uploaded file named window housing 2.jpg
Thumbnail of the uploaded file named window housing.jpg
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Bob from SWISCO responded:
August 10, 2020

This looks like the 15-102 Coil Spring Carrier, which uses our Series 145 Coil Balances. These coils and their components are held firmly in place when installed into the window jamb. Basically, they plop right into place! Let me know if you have any further questions. 
Double Side Load Carrier
Double Side Load Carrier
15-102
$2.65
Sash Cam
Sash Cam
15-108
$1.28
Sash Guide Base
Sash Guide Base
15-222
$1.40
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