Training Cave diving training includes equipment selection and configuration, guideline protocols and techniques, gas management protocols, communication techniques, propulsion techniques, emergency management protocols, and psychological education. Most training programs contain various stages of certification and education. Cavern training explains the basic skills needed to enter into the overhead environment. Training will generally consist of gas planning, propulsion techniques needed to deal with the silty environments in many caves, reel and handling, and communication. Once certified as a cavern diver, a diver may undertake cavern diving with a cavern (or greater) certified "buddy," as well as advance into cave diving training. Introduction into cave training will builds off of the techniques learned during cavern training and includes the training needed to penetrate beyond the cavern zone and working with permanent guidelines that exist in many caves. Once intro to cave certified, a diver may penetrate much further into a cave, usually limited by 1/3rd of a single cylinder, or in the case of a basic cave certification, 1/6th of double cylinders. An intro cave diver is usually not certified to do complex navigation. Apprentice cave training serves as the building block from intro to full certification and includes the training needed to penetrate deep into caves working from both permanent guide lines as well as limited exposure to side lines that exist in many caves. Training covers complex dive planning and decompression procedures used for longer dives. Once apprentice certified, a diver may penetrate much further into a cave, usually limited by 1/3rd of double cylinders. An apprentice diver is also allowed to do a single jump or gap (a break in the guideline from two sections of mainline or between mainline and sideline) during the dive. An apprentice diver typically has one year to finish full cave or must repeat the apprentice stage. Full cave training serves final level of basic training and includes the training needed to penetrate deep into the cave working from both permanent guidelines as well as sidelines and may plan and complete complex dives deep into a system using decompression to stay longer. Once cave certified, a diver may penetrate much further into a cave, usually limited by 1/3rd of double cylinders. A Cave diver is also allowed to do multiple jumps or gaps (a break in the guideline from two sections of mainline or between mainline and sideline) during the dive.