Even veteran cavers sometimes do not realize just how low that rock ceiling really is and stand up right into it. A proper helmet with liner is a critical piece of safety equipment for every caver. These helmets can range from a cheap construction site hard hat to a $300 specialized caving helmet (in 2009) that comes with a matching head lamp.
As important as a helmet is, the head lamp offers a beam of hand's free light that will go wherever the caver is looking. This has been standard underground gear since the 19th century days of the kerosene head lamp. Many caver helmets come with their own lamp, or at least a mount meant for a particular family of lamps. For those using a hard hat or other kid of helmet for caving, there are lamps that can be attached to any helmet by means of straps, and these in 2009 cost between $20 and $50.
Crawling through caves is dirty, rugged fun, and caves typically have temperatures in the 50s. Cavers need an outfit that can be dragged through mud, over rocks, and keep them warm. Most wear an outer layer of coveralls, which in 2009 cost between $20 and $50.
All cavers need secondary lighting, both to supplement their head lamps and as a back-up in the event of a head lamp failure. This typically takes the form of either a common flashlight, glow sticks, or both. Many cavers also carry replacement batteries and light bulbs for their head lamp.
While overalls have pockets that are useful for carrying gear, it's not comfortable to have pockets full of items when going on a belly crawl. Backpacks, on the other hand, are perhaps too much carrying capacity and get in the way in tight spaces. The best balance is a buttpack, which can be had from Army surplus shops for between $10 and $30. This is also a convenient place to keep a water bottle.
Cavers spend a lot of time crawling in tight spaces, and this is done on rock or hard, compacted dirt with solid rock beneath it. That is very hard on the knees, so all cavers need knee pads. A good pair of knee pads with a solid, exterior plate can be purchased for $30 to $40.