Trying to ID these bags purchased ~1980 ...

I bought these bags in 1980.
I had seen them around surplus stores off and on for several years.
I think I had seen them with medical and /or chemical insignias stenciled on them.
I bought these to use as saddlebags for a motorcycle road trip to Alaska.
They did the job nicely.

They came with "CY - I064A/ATC" stenciled on them.
So, my question is: What are they?

EDIT:
I took a look inside one of the bags and found stenciled on the inside end of the bag:
ORTHOPEDIC EQUIPMENT CO., INC
USA 120-68-C-3448

This lends credence to my calling them medical duffels through the years.

https://www.milsurps.com/images/impo...IMGP0215-1.jpg
https://www.milsurps.com/images/impo...IMGP0219-1.jpg
https://www.milsurps.com/images/impo...IMGP0217-1.jpg
https://www.milsurps.com/images/impo...IMGP0222-1.jpg

With the US mark on the inside it appears to be rigger made?

Quote:

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Originally Posted by conec

With the US mark on the inside it appears to be rigger made?

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Being not very knowledgeable about military equipment terms "rigger made" threw me.
After looking around a bit, I understand it to mean contract supplied non-standard equipment in this instance.

So, I looked up the supplier, OEC, and found this:
Founded in Warsaw, Indiana in 1942, OEC originally marketed to orthopedic surgeons--hence, its name at that time: "Orthopedic Equipment Company.' OEC's equipment for orthopedic surgeons originally included pins, plates, and other orthopedic devices necessary for correcting skeletal deformities in patients. In the process of marketing these orthopedic devices, it became apparent that providing real-time imaging to the surgeon would be an invaluable tool; thus, in the early 1970s, OEC moved in the direction of mobile X-ray imaging.

This leads me to believe that these bags were used for packing x-ray type equipment components used in mobile hospitals.
Does that sound reasonable?

I saw many of these bags off and on in Seattle area surplus stores in the mid to late '70s.
They were made of a very heavy canvas and were very sturdily made.
Using a couple of Alice Pack shoulder straps to fasten them together at the D-rings, they slung over the back of my motorcycle and held enough gear to spend the summer on the road camping out in reasonable style.