Masks, snorkels and fins: the basic kit.

Masks

PADI explains that the mask's skirt has to enclose the nose, because the air space inside the mask must be equalised as the diver descends. PADI describes the skirt as soft silicone, typically with a feathered, double-layer edge where it meets the face.

For the lens, PADI's 2015 buying guide says it should be tempered glass strong enough for diving pressures, while PADI's gear page says lenses are typically tempered glass or a strong, high-quality composite.

Volume and skirt colour

PADI separates masks by internal volume:

• Low-volume (low-profile) masks sit closer to the face and clear of water more quickly.
• High-volume masks feel more open and widen peripheral vision, but take more effort to clear.

For skirt colour, PADI says clear silicone lets in more light and feels more open, while a dark, opaque skirt cuts glare and is often preferred by underwater photographers.

Features and fit

Some masks have a one-way purge valve for clearing water, and some take prescription lenses or optical inserts; PADI suggests asking a dive professional about the options. Above any feature, PADI names fit and comfort as the deciding factor, ahead of price or colour, and recommends trying masks on at a dive centre.

Two care notes from PADI apply from day one. A new lens usually carries a residue from manufacturing that needs cleaning off to reduce fogging, and a defog product is used before each dive. Black neoprene or rubber, including some fins, can stain a clear silicone skirt if the two are stored touching.

The mask standard

EN 16805:2015, "Diving equipment, Diving mask, Requirements and test methods", is the CEN standard for masks that protect the eyes of a person breathing underwater. It does not cover full-face or oro-nasal masks. The Estonian standards catalogue lists it as valid from 5 January 2016 and shows it as the current entry. A search summary of a BSI committee page, which we did not open ourselves, described the British adoption as withdrawn from 1 April 2016, so its status in the UK is not confirmed here.

Snorkels

EN 1972:2015, "Diving equipment, Snorkels, Requirements and test methods", covers snorkels used for breathing at the surface while floating face down, by swimmers and divers alike. It excludes combined mask-and-snorkel units in which the tube opens into the mask. The Estonian catalogue lists it valid from 5 January 2016, with an earlier EN 1972:2000 in its history.

A US dive retailer describes three common designs, though we could not open its page to confirm the wording:

Classic J-style

A plain tube.

Semi-dry

A splash guard on top and usually a purge valve at the bottom; it still floods when fully submerged. A flexible lower section is common.

Dry-top

A float valve closes the top when the snorkel goes under.

The same retailer notes that valves and splash guards have moving parts that sand can jam. Scuba Diving magazine's 2012 review of one dry snorkel reported the maker's design claims: a top valve that shuts underwater, a self-draining lower chamber and a mouthpiece designed to drop away from the face.

Fins

Full-foot or open-heel

Fin maker Atomic Aquatics claims that a well-fitted full-foot fin gives more sensitivity and thrust than an open-heel design, and recommends open-heel fins with boots for cold water and rocky shores. Those are the maker's statements.

Blade designs

PADI names four blade types:

• Paddle: a rigid blade with good control that takes more leg effort.
• Channel: soft sections flex into a U shape to direct water.
• Split: works best with small, quick flutter kicks and is easier on weaker legs, but less precise for turning, backing up and frog kicks.
• Hinged: the blade pivots, making it soft to kick but less manoeuvrable.

Straps

For fin straps, PADI lists basic adjustable straps (often with ratchet buckles), quick-release buckles, extending buckles, which it calls the most prone to breaking because of their extra parts, and spring or bungee heel straps that slip on and stay snug. Because a broken strap makes a fin unusable, PADI recommends carrying a spare.

The fin standard

EN 16804:2015, "Diving equipment, Diving open heel fins, Requirements and test methods", sets minimum safety requirements for open-heel diving fins and is listed as valid from 5 January 2016. Our research did not find an equivalent CEN standard for full-foot fins.

What a standard means for a given product is set by the standard and the maker's own marking; this page does not say any product meets one.