I can use this Din Rail for circuit breaker?

if your going to use a din rail circuit breaker like these you can https://www.amazon.com/s?k=din+rail+circuit+breaker&crid=U06FCZL9H30B&sprefix=din+rail+circuit%2Caps%2C163&ref=nb_sb_ss_ts-doa-p_1_16

can this be used to hang Akro plastic bins?

Unfortunately, I have never seen an Akro plastic bin hung on DIN rail, but I would check to see if the bin is mountable on DIN rail 35mm wide and 7.5mm high. The 35mm DIN is will be the most important specification listed. Clayton International Connector, Inc.

I would like a DIN rail that would be long enough to mount in a 19” rack

The center to center spacing on this aluminum rail is just under an inch, so a 19 hole piece of rail would measure closely to 18 11/16". Would that be the size that you are looking for? Kindest regards, Clayton International Connector, Inc.

Are there 1 or 2 pieces included, if one you need to change your description?

There are 2 pieces included with this item. If you received anything different, please call the Amazon Customer Service phone number at 1-888-280-4331 so they can replace your item with the correct item. I was on the phone with Amazon a week ago and they said they did a full bin check and assured me only 2 pieces are currently being sent out. You can also reach out to me directly if Amazon doesn't fix the problem for you. If you are looking for our 1 piece listing, you can find that in the link below. https://www.amazon.com/dp/B01FT485S0?ref=myi_title_dp Kindest regards, Clayton International Connector, Inc.