The Colantotte Bracelets are a small pair of bracelets given to Tony Stark by Pepper Potts during one of their first dates as a couple. The bracelets inspired Stark to design the Iron Man Mark VII Armor, allowing it to find and attach to its user.
Pepper Potts managed to have a date with Tony Stark, realizing that, given the time spent in that place, the basement of Tony Stark's Mansion in Malibu would be the ideal locale. To celebrate their date, Potts gave Stark a gift, a pair of Colantotte Bracelets used in Magnet therapy.
Stark researched about the bracelets, finding information about how the bracelets used alternating north-south polarity orientation to maximize magnetic field flow. This effect supposedly improved blood flow, among other benefits, for the body. Potts revealed she thought it would be a good gift, given Stark's complaints about his pains after each battle as Iron Man. The bracelets inspired Stark into creating another model of the Iron Man Armor.
Stark put on his pair of bracelets as he confronted Loki in Stark Tower, anticipating that something may go wrong. Stark was proven right as Loki threw him out of the window. Stark ordered J.A.R.V.I.S. to deploy the Mark VII Armor, which was able to recognize the bracelets and catch him before he hit the ground.
The bracelets appear to work with the Mark VII through a method similar to a laser barcode scanner. When the Mark VII is deployed it will fly to the user while scanning for the bracelets. Once it locks onto the bracelets it will attach to them, using them as a reference/starting point while assembling itself around the user.