@Francesco I use the Ringke Fusion: http://www.amazon.com/RINGKE-Selling-Absorption-Scratch-Premium/dp/B00B7QGT6U/ref=sr_1_1?ie=UTF8&qid=1417445165&sr=8-1&keywords=nexus+4+ringke+fusion

I have that set up and I am using a normal ring I have 3 and they all work flawlessly even with the case on. That shows where it reads the best on my phone (The sweet spot sticker) and the orientation to have the ring on case.