These are great pads but before you rush out and buy some, consider whether they will fit your holders and also what you will need to do to replace the existing pads.
First of all, measure the length of your existing pads.
The Kool-Stop replacement pads are 40 mm long. These are great pads and the black ones look just like the original Campy N/R or S/R pads, except on close examination. They were in fact intended as replacements for the early (1960s-80s) Campagnolo pads.
However ... your holders appear to have both ends closed rather than one end open like old Campy. Still, I have also used those pads even on old Weinmann holders (with all 4 sides closed) when I could not quickly get suitable (and cheaper) copies of Weinmann pads complete with new holders. Those Weinmann "X-style" pads from the 1970s through 1990s measured 38 mm long, but the additional 2 mm length I did not consider a big deal and was certainly barely noticeable at all on the bike.
So, if these pads are the same length as your existing pads, or close enough for you to use... this is what I did on my holders to modify them to accept replacement pads:
1.) You can just push the old pads out by inserting a thin flat screwdriver blade into one end of the holder and then pushing (prying) the old pad upward and out. I have also used these pads on Mafac holders, and also old Universal holders. They really work fine on a number of older brake pad holders. And they look a lot more natural and less distracting than the long high-tech modern pads.
2.) Since both ends of the holder will still be closed after removal of the old pad, you would need to firmly grip one end with a narrow jaw pliers (or a small cheap 5" long "vise-grip" plier works very nicely). Bend the end down to open up the holder. Personally, I just rocked the end repeatedly back an forth along the natural bend and let rapid metal fatigue quickly break the end at the elbow already formed from the original closure bend.
3.) To "finish" the now cleanly broken off but sharp or jagged end, I just used a simple 6" file. A few passes smoothed the edges of the open end quite nicely. I now had a holder suited to accepting future replacement pads.
4.) Then you can just slide the new pad in by pressing it along the channel of the holder from the open end. ~ A little grease rubbed on the part of the new pad which will be concealed inside the holder will help ease the naturally grippy rubber of the new pad into the holder.
Here is a very cheap pair of generic holders which had badly worn pads but happened to be a good length for these Kool-Stop pads. A quick and easy modification... and not bad looking at all.
[Excuse the quickie kitchen counter top photo...]