The Lumo can even correct your posture by gently vibrating to remind you to sit straight. This can make all the difference in the world. All that we need sometimes is just a reminder to sit up. The device syncs to your iOSS device via bluetooth 4.0. You can wear it discreetly under your clothes or over your clothes if you like. The dimensions of the product are 1.75"W x 1"D x .5"H.