Take your typical round flashlight, toss it up a few inches and catch it. Feel the batteries bouncing inside? Don't you think it's a bit sloppy for a hi-tech tactical electronic aircraft-grade anodized machined aluminum light? I thought so too. So I took my MTE C3-907 apart and applied a thin layer of silicone on the inside. I used an old battery greased with motor oil to size the silicone. After the silicone cured, I honed it so a battery would slide in an out with just a bit of friction. Now my flashlight feels like a solid piece.