No surface intervals. No air fills. No mechanical equipment problems. To fully understand this sport, one needs to look at the physical, and material aspects that make up this unique experience. The material aspects of this sport, which are minimal, make this a very appealing sport for anyone looking to experience the ocean realm.
Lets take a look at the equipment requirements for freediving.
The mask is our window to the underwater world, and as such needs to fit comfortably during long sessions of diving and yet not leak. Many experienced freedivers prefer not to use clear silicone masks, but instead use the black silicone equivalent of a given manufacturers model. It also is more comfortable to wear for long periods of time, seeming to be softer and more pliable than its clear equivalent. As such, the mask, should be very low in volume, and very soft, with a comfortable skirt so your face seal is perfect, for many hours at a time in the water. The Italian Dive equipment makers Cressi-Sub and Mares make excellent masks.