markz
100 TW
https://sheldonbrown.com/inner-tubes.html
In some regions, notably the Southwestern U.S., "goat-head" (tribulus terrestris) thorns are so common that thorn-proof inner tubes are a desirable option. They are thickened under the tread to help prevent flat tires. These tubes are not only heavier but also increase rolling resistance. They make your wheels heavy and sluggish, and, if incorrectly installed, they can actually cause flats! They can make sense in areas with "goat-head" thorns. Sealant, a liquid inserted into the inner tube which closes small holes, and aftermarket tire liners, such as the well-known Mr. Tuffy, are other options.
Ditch the jam nut
Some inner tubes have a valve stem threaded all the way down to the rim, and a knurled jam nut to clamp the valve stem to the rim. I (John) know that Sheldon's photos show this nut in place on the Presta and Woods valves, but it has only one use -- to make installation of the pump head slightly easier when the tire is uninflated. The valve stem is more likely to bend, break or pull loose from the inner tube if clamped down. It is easy enough to pinch the tire between finger and thumb to keep the valve stem extended when installing the pump head.