I have a friend who is getting into running more and more. She used to have an armband that held her ipod against her arm and she would simply leave her phone at home. She'd like to switch to carrying her phone with her instead, but is fussing because she's tried a couple different bands now and they don't work. Either they're too tight and cut off circulation, or they slip and slide down her arm eventually, even if they don't feel too loose to begin with. Got any reliable suggestions of what to use instead or a decent brand of armbands to try?