I usually just cut bicycle inner tubes into whatever size “ranger band” I need but they can get brittle and tear in a relatively short amount of time. GEARWARD is now offering a more substantial Ranger Band. Theirs are made from thick EPDM rubber which, according to GEARWARD, resists heat, UV, and saltwater. Like most rubber bands, these can be burned as an emergency fire starter but thanks to their thick construction, they burn for 3 minutes.
The bands are 2″ long, 1/2″ wide, and come in packs of 20. Check out GEARWARD Ranger Bands.