Getting ready for our tour 26 May. In searching for adapters taken on previous RS tours I learned/discovered that Switzerland has its own configuration Type J while Germany Austria use Type E/F. Glad I checked :-)
The standard 2 round prong euro adapter has always worked fine for me in Switzerland. I am only plugging in low power things like a cell phone or camera charger. Not grounded.
Those (type E, F, & J) are grounding adapters. Most 2-pin, non-grounding, type C, Europlug adapters will fit in Swiss receptacles.
The Europlug adapter is for unpolarised (both blades equal width) US devices drawing less than 2½ amps (575W @ 230V). That includes USB converters for phones, laptops, etc. Swiss power is polarized. Polarized US devices can be used with a properly configured, type J, adapter. The Europlug adapter can be inserted opposite ways in a Swiss receptacle so polarization cannot be assured.
But many are interchangeable. We went on the best of Europe tour through France, Germany, Switzerland and Italy. If I recall correctly, the mainland Europe type C was usable in all of these countries. Here is a handy web page that speaks to the adaptors.
But do note, this is only for the plug adaptor and not the power rating. However, we found that our Nook and iPhones all had internal converters such that nothing more was needed other than the plug adaptors.
Is the plug on your appliance 2-pin or 3-pin, i.e. is it earthed?
Swiss 2-pin plugs are the same as the surrounding countries. If you have a 2-pin adapter (photo: https://www.dhresource.com/0x0s/f2-albu-g5-M01-F9-5D-rBVaJFg_0kyASxz1AACiu5nEdVs206.jpg/us-usa-to-eu-euro-ac-travel-power-socket.jpg ) with triangular ends, as shown, this will work in Swiss sockets.
Swiss 3-pin plugs are different from surrounding countries. If your appliance is 3-pin, you need a 3-pin adapter specially for Switzerland (photo: https://sc01.alicdn.com/kf/HTB19mCQSpXXXXanXVXXq6xXFXXXm/White-color-Type-J-3-Pin-Plug.jpg_350x350.jpg ) Again it must have triangular ends, some foreign-made ones don't.
France+Germany+Austria use the same plug (but different from Switzerland). Italy is different again.
The adapter does not have to have pointed (triangular) ends. I haven't been in Switzerland recently long enough to personally check, but I found dimensions for the recess on a Swiss receptacle online and compared it to my "round-ended" Europlug adapter, and the adapter would fit. However, I have an older (ca. 1980s) adapter with very large rounded ends (looks like a dog bone) and it would not fit in a Swiss receptacle. It also has both blade slots of equal (narrow) width, so a polarized US plug would not fit in it.
I don't own a square-ended adapter like the "Continental" one sold by RS, so I haven't checked it, but the ends are fairly short, so I think it would fit. RS's Universal adapter has pointed ends and, presumably, would fit.