The whole field of small electronic modules just changes and morphs so frequently. Manufacturers, dealers distributors and models change almost daily. It is a great day to experiment with electronics because there are so many inexpensive modules available these days.
Here's a picture of my counter. Just tacked it to the door frame. It's LCD with no backlight so the internal battery will last ~7years. It also uses contact closure so no external power is needed. I just use a security magnetic switch at the top of the door with the magnet on the door itself.
ENM are quality units, but finding them and sorting through their catalog is a pain. Then finding a distributor for quantity One is also a challenge. DigiKey is one, but their catalog stinks too. Trumeter & Redding are other good companies. There are others.
Now if you want a cheap one from China with the mag switch included, but requires a AA battery.
https://www.amazon.com/Yeeco-Shockproof-Electronic-Totalizer-Accumulator/dp/B07D6M8H24/ref=sr_1_4?dchild=1&hvadid=77996658660364&hvbmt=bp&hvdev=c&hvqmt=p&keywords=totalizer&qid=1597683321&s=industrial&sr=1-4&tag=mh0b-20Picture is my ENM Unit not the Amazon unit