What do you call the place where you tie a horse

Good question, and one that most native English speakers won't even get correct.

The icon you circled shows the strength or quality of your wifi signal as measured in bars.

Bars doesn't really mean much, though: it's not a regulated unit of measurement like grams or decibels. Different systems use different amounts of bars, so what's important is how many bars you have out of how many bars there are total.

You could say "My WiFi signal is very weak: only 2 out of 5 bars."

And were it a better signal...

"My Wifi signal is okay: 3 out of 4 bars."

"My Wifi signal is really strong: full bars!"

JewelryShoppingGuide.com suggests that it might be called a cuff bracelet.

Note that "cuff" as in handcuffs carries a meaning in English that is similar to shackle but less so, or at least that is how I see the terms:

• Handcuffs are used on people who have been arrested and are being transported to a police station, or on prisoners who are temporarily outside of their jail cell (e.g. in a courtroom). They bind the prisoner's wrists together.
• Shackles are a more permanent restraint, used for long-term punishment. The shackle fits around the prisoner's wrist and is attached to a length of chain which is bolted into a wall, or perhaps it fits around the ankle and is attached to a heavy object (the proverbial "ball and chain"). I'm no expert but it seems like the use of shackles would likely be deemed "cruel and unusual" today. When I hear the word "shackle" I think of a medieval dungeon, not a modern prison.

It might be the case that in certain cultures (like Japanese/manga fandoms) such pieces of jewelry are called shackles. But unless you know that for sure, it would be safer to call them cuff bracelets.