This is the thread we use on our uniforms and gear. All is made in the USA by Coates or A&E, much of it being custom dyed for us to match originals. Of our threads, the only stock color you can find in a store is the black. (The original German thread is made in Germany.)
Quantity: We have wound it onto wooden, period looking bobbins that look fine in your sewing kit or repair box. Each contains about 50 yards of thread- we use the bobbin filler attached to one of our sewing machines- which doesn't have any sort of counter- so it's not an exact quantity- we simply wind until the bobbin looks full. I reeled off two of our bobbins and one had 57 and the other had 64 yards of thread. So that's how I arrived at "approximately 50 yards." This is enough for most any repairs or sewing insignia. (The size 110 thread is much thicker so I estimated 30 yards.)
Some thread is 100% cotton and some is cotton wrapped- which means there's a center core that is polyester with cotton fibers covering it. Unless it's burned, there is no way to detect the polyester. It's not visible.