It hopefully will stay, given that this is an important and most elegant part of the penis.
The GlansPro? I hadn't seen it before either but am fascinated to note the profuse marketing "hype" on their page.
They correctly note the primary problem of the "Glansie" as having too "pointy" tips on the instrument to be useful for other than initial treatment of the tightest forms of phimosis, but the fact is, their device is little better. They also promote the fact that it has no "lock" to hold the stretch - you have to do that with your hand, which is clearly tiresome and rather than producing more consistent stretch, is likely to make it more erratic. I won't comment on the price because good surgical instruments do cost similarly.
If you want rapid stretching results, you want a "device" as described elsewhere, that you can keep in place for hours at a time, progressing to all day and even night. But basically, our advice is always to get going with the finger stretching - and do it right now!