I still have about 875 tubes that are very similar to these on Amazon. I got mine locally when a lure company went out of business. They had several boxes of new tubes and caps that came 1,000 to a box. Just couldn't pass up 1 box since they were inexpensive, and I knew I'd find many uses for them.
https://www.amazon.com/Clear-plastic-storage-tubes-diameter/dp/B01EEVZCZI
Mine are clear plastic, with pull off, black, end caps. They're 3.75" long x 26mm diameter. I can easily fit a TTM (without drip tip) and then a 24mm Berserker (with drip tip) on top of it, since the Berserker 510 fits down into the drip tip hole on the TTM. The clear plastic is easy to cut with scissors too, so I can customize what length I need/want them to be.
I've used some for bead storage, for vintage crystal necklace storage, have taken tanks and factory coils in them on vacation, used some for screws, nails, nuts & bolts, etc. I also use some, with 1 end cap taken off, to put over my tanks not currently in use, in a tank stand.