What Bryan said. Device rotates about the top tube with bumps, when loading, unloading. I bought it to hold my power supply. I thought that, since it is twice the thickness of a phone, it would be tighter and not slide around, but it made little difference.
Can be used for something
Brian on 8/27/19
I initially bought this to attach my cellphone to my handlebar. Based on the dimensions It should have fit my Samsung S5 with no problem. The problem was that the band that wraps around the handle bar to attach the device is quite slippery. Once attached, and you continue to stretch the same band over your phone, the device spins on the bar as you try to pull the band over your phone to lock it in. I got tired of this and decided to attach a smaller device in it. I had bought a pocket radio with a weather alert feature. It was smaller and not as hard to attach to the device without it spinning. Although, as you hit bumps, the device does move but can be moved back with a little twist. Not a bad design but perhaps a material with more tack could have been used.