If these are the same ones I bought a few weeks ago, they will work with the Samsung Galaxy S8+. They will work with an Otter box Defender case as well, but I have had to turn my phone on its side to get the induction charging to actually work. If I set it upright while in the Otterbox case, it says it’s fast charging, but never charges past it’s current charge state. Thats probably due to the positioning of the induction coils.
I have the same 2 brand new from the last woot but wifey didn’t want them after all. If someone wants them for $35 shipped just private message me.