the imren is the same size as the vtc5. I did not have the battery seated in the center of the tube. it is easy to get it a little crooked and then the cap will not screw flush. I couldn't imagine they made so it wouldn't sit flush. now that I figured that out both batteries fit fine. you can even screw it indented but flush is going to let it stand more stable. I need to go to the hardware store and get something better than a quarter. since 40+ watts is not going to cut it on usb. I will be swapping batteries. hope the cap holds up. tube looks like thin copper. the fact that it is copper leaves no doubt this is top of the line. not that poopy spring in ipv's.