If anyone from General Tools is reading this review, the kit would be far better if it came with 50 male and 50 female eyelet halves to grip the host material firmly and look better. I can't recommend this product as it is; it did the job but it took some improvisation on my side and way more effort.
I wanted to set an eyelet in the phone cover for both me and my wife so a wrist strap can be attached. When I used the pliers to force the piece through the leather and then squeezed to flatten it out, I found that the "post" on one side of the tool was stuck in the eyelet and I had to use an eyeglass screwdriver to detach it. Having done that, I found that the leather in the hole was still hanging on and more importantly, the metal had folded over very little and so it was barely gripping the leather (top photo).
I used the tool again in an attempt to flatten it further but that didn't help, though it did deform the metal (center photo).
To achieve what I wanted, I applied a SECOND piece from the opposite side so that the leather is held firmly from both sides and it looks great (bottom photo). It looks slightly mangled on the other side. Since the second metal piece is the same size as the first before it was deformed, this has to be done carefully so it goes through evenly. I practiced first by doing my own cover and several times on one section of the newspaper so I knew that when doing my wife's, to do it first from inside the cover to out, then outside to in, so the better looking side was outside.
This product would be better if it had separate top and bottom pieces like the "1/2 in. Solid-Brass Grommet Kit" (http://www.homedepot.com/p/General-Tools-1-2-in-Solid-Brass-Grommet-Kit-71264/100200416). Arguably, it also needs the sharpened cylinder seen in the grommet kit to make the hole before inserting the eyelet.