I use a Topeak cell phone holster that attaches to the bike just below the Stem. It slides off to double as a belt holster when I am not riding. If I am not on the road bike it goes it goes in a cargo pants pocket. If someone jacks my bike my cell phone is the least of my problems. To get the bike they had to knock me off of it. But in the holster it is easy to reach if for some reason I need to make a call.