Well, my thimble is leather rather than rubber and the metal part looks somewhat different from the photo. I haven't found mine online; not sure it is made anymore. In the link below, "B" is the thimble that looks the most like mine, except mine has leather around the finger instead of metal:
http://www.quiltuniversity.com/w/HandQuilting.htm
I bought the McElroy thimble but never learned to use it easily. A lot depends on whether you are more comfortable using the side of your finger, the pad of your finger, or the tip of your finger. I prefer pushing the needle with the tip of my finger, which is why I like the type of thimble I described. I used the same thimble underneath because the ridge does a good job of pushing the quilt sandwich up for the needle.
A common beginner's mistake is to hoop your quilt too tight, like a drum. There should actually be a lot of "give" in the hoop. Roxanne told us to hoop loosely, so we could fit a fist into the center of the hoop. This looseness allows you to manipulate the quilt sandwich up and down so you can "load" the needle with stitches.