Caving Bags & BackPacks
There are different types and sizes of caving bags. They are dragged, dropped, submerged and otherwise treated quite brutally. In most cases, bags with zippers won't work for very long, so drawstrings, buckles, or clips that are mud and moisture resistant usually work better. Not all caves are wet, so bags / bags do not necessarily have to be waterproof, and any waterproofing is likely to leak over time, but for wet caves, bags must either have waterproof functionality that is retained or equipped with drainage holes.
Some cavers have nothing more than a small shooting bag with just a few basics, but for most cavers, a daypack has a volume of 8 to 25 liters (500 to 1500 cu-inches). For an easy horizontal recreational tour, a bag is sufficient to carry some food, water, a small repair and first aid kit and some spare batteries and a headlamp. A vertical cave research strip may require a larger 25 to 40 liter (1,500 to 2,500 cu-inch) bag. Typical camp packs range from 40 to 60 liters (2,500 to 3,500 cu-inches) and require sleeping bags, sleeping mats, cooking appliances, extra food, tarps, etc.
There are a few basic bag types designed specifically for caving:
These are based on one of the classic original cave bags - the army surplus gas mask bag. The standard in American caving for many years. A very similar backpack, in different sizes and configurations. Side packs have two wide adjustable straps and typically five D-rings that allow the pack to be worn as a traditional backpack, fanny pack or side bag. The side pack configuration is the most popular and is a very efficient way to carry a pack through a lot of chimney climbing and crawling.
The standard bag used is a round or oval bag with two shoulder straps and a drawstring closure at the top. You can take a lot of things with you in these bags, they are simple, light and durable and are easy to drag or tie when crawling or on a rope respectively. Most of the larger camp packs are of the tackle bag variety, and some, have a roll-top closure instead of the drawstring variety.
Some cavers put a shoulder strap around a dry bag and use it like a cave bag, but they wear out of course. These cases are often made from a urethane coated fabric that is extremely abrasion and puncture resistant. Another waterproofing option is to use a tackle bag with drainage holes with a dry bag inside. Alternatively, a container can also be used.
See also the pages under the rubric Packs, bags & duffels of canyoning