The tube that came with your new fly rod likely weighs a pound, possibly more. That's a lot of needless, extra weight when hiking to wilderness lakes. The simple to make, ultralight, inexpensive solution is a DIY rod tube that will save at least 1/2 pound on your next hike to alpine lakes. An Amazon 2" to 3" diameter x 36" length cardboard mailing tube with plastic end caps will do the trick. Measure the largest diameter of your rod including reel seat and line guides in its rod sock to determine whether a 2", 2 1/2", or 3" diameter tube is needed for your specific rod. For most fly rods a 2" outside diameter multi-ply cardboard mailing tube works great.
Saw it to the length needed to fit your 4 piece rod,
spray with a couple coats of urethane to waterproof,
wrap each end with 2" wide filament/strapping tape for reinforcement,
insert a small wad of bubble wrap on each end for padding,
and seal the ends with the plastic caps included with each mailing tube.
Adding a couple blotches of bright colored spray paint on the outside makes it very visible and easy to find when sitting on the shoreline separate from your backpack. Complete it by taping your name and address/business card on the outside. A 31" long x 2" diameter completed ultralight rod tube to carry a typical 9 foot, 5 weight, 4 piece fly rod is ready for your hike, and it weighs just 6.1 ozs. Keep your rod inside its cloth rod sock, insert it into your ultralight rod tube, and hit the trail. The DIY rod tube fits well in a side pocket of many backpacks, and is great as a carry-on item for airline travel to be certain your rod arrives with you at your destination.
The DIY tubes used by the Wilderness Lite team have many weeks of use in the wilderness and many miles on the trail in all weather conditions, and are going strong.