Both of TankT5’s layers are quite thick, and taken together they add noticeable size to the thin device. Part of this comes from the abnormally deep lip surrounding the iPod’s screen; it’s going to keep the display safe from drops, but it’s a bit taller than necessary. The rest of the bulk comes from the thick rubber around the edges on the back of the device, and the plastic that sits flush against it when laid in place. This…