This hose will fit between the shower arm and a hand-held shower head. It is a long hose. I use it to bathe a small dog in the tub and rinse grandkid’s hair. It’s perfect for that!
Soak the shower head in vinegar should do the job.
Yes, the shower hose was kink free when I purchased it and I haven't had a problem with it kinking since then.
No, model HOS-396M does not include a flow regulator.
I assume you are asking the size of the threaded fittings at either end of the hose, and those are a standard 1/2". The inside diameter of the hose that the water actually flows through, looks like it is about 1/4", which is more than adequate to feed a hand held sprayer.
Yes, it will work.
The connection pieces are plastic.
It did not fit my Delta hand held shower wand holder. If all the Delta holders are the same, it would not fit yours either.
The hose expands when under water pressure. I believe the 8' length is related to the length before water pressure is introduced.
Yes - that is its main purpose.