I purchased Mine off Amazon. I picked the one with the best reviews and number one sold. It cost $15.99 with no shipping on prime.
I was skeptical I opened the packing box that weighed nothing. However I have been pleasantly surprised. It's very accurate. I have tested it against my other therms and its within 1 degree. It takes 3-5 seconds to get a solid reading. I've found myself running around the house shooting everything to check temps for no reason. I'll probably wear out the two AAA batteries that came with it just temping dumb stuff.
Now for the purpose that I bought it for. It works great. I can get an accurate reading and know what temp my disk or the oil in the disk is. I can see using this for checking temps in the DO too. I'm really particular when I want to fry onion rings or taters. Now I have a great way to check the temp of the oil.
It's easy to use, no complicated instructions or buttons. Has a red dot laser sight so you know where you are reading the temp from. Auto on, auto off. Just pull the trigger and shoot.