1. Dive Alert Plus

How loud is the Dive Alert Plus? For the record, it puts out 132 decibels, but we can say from experience that it’s train-horn loud; you’ll be the least-popular diver on the boat if you inadvertently toot at your fellow divers. It works with as little as 100 psi and installs without tools, clipping in between your inflator hose and BC inflator (there’s also a version for inflators with an integrated octo). It also works underwater, sending out a buzzing noise about as loud as most noisemakers. But it does its most impressive work at the surface, where it’s loud enough to be heard a mile away. $79.95; divealert.com

2. DAN Signaling Sausage

When it comes to surface signaling gear, size definitely matters. DAN’s sausage is a full 6 feet long. It’s also bright orange, covered with 2-inch-wide reflective tape on both sides, and has a radar reflector inside. At the bottom it has a hook-and-loop strap to keep it rolled up, and a built-in mesh pocket to store safety supplies. You can inflate it with the oral inflator, connect it to a low-pressure inflator hose or fill it through the oneway opening in the bottom from your regulator purge. $60; diversalertnetwork.org

3. XS Scuba PLUS Lighting

All divers tend to look alike at night, but PLUS could change that. It stands for Peripheral Lighting Underwater System — a flexible plastic tube of LED microlights that threads through small elastic loops mounted around the perimeter of the BC, with a battery pack/ switch that stores in a cargo pocket. We tried it with XS Scuba’s SeaBlazer jacket BC, but it also works with the back-inflation Phantom BC. It takes about 10 minutes to install. They’re visible from 360 degrees around the diver, and provide enough ambient light to see your gear. We tried it with white lights, but the PLUS system is available in several colors, so you can use them to help keep track of buddy teams, students or dive guides. $99.95 separately, $85 with BC; xsscuba.com

4. Scubapro Flashy LED Flash

Smaller than the tip of your thumb, this clip-on flashing marker light helps your buddy keep track of you even when your light’s out. It pulses with a soft, unobtrusive glow; when we tried it during a night dive, it was visible at a surprising distance underwater. It twists on and off, and is rated to 328 feet. The watch-style microbatteries are user-replaceable and burn for 12 hours. $16; scubapro.com

5. Underwater Kinetics Aqualite S20

If it’s a good idea to carry a backup light at night, it’s an even better idea to carry a backup that’s capable of doubling as your primary light. Less than 6 inches long, the S20 pumps out 500 lumens on high power, runs for up to 13 hours on low power, and has a 20-degree beam that provides a useful coverage area as well as good penetration even in less-than- optimal viz. We liked the way the tail switch makes for easy one-handed operation. The S20 uses a rechargeable Li-on battery and comes with a quick-detach rubber hand mount. $199.99; uwkinetics.com

6. Light & Motion Sola Video Spot/ Flood 2500

The Sola combines the capabilities of two very different lights for an incredibly versatile, do-anything dive torch. It has the wide-angle beam of a video light powerful enough to illuminate a broad area and the concentrated narrow beam of a more traditional dive light able to pierce through even the murkiest water. You control it with the top-mounted magnetic switch, which slides fore and aft for quick changes between the 60-degree wide and 12-degree narrow beams and power settings from low to high (plus an SOS flash).

On its highest power setting the Sola verges on too bright for many dive applications; fortunately the switch makes for easy changes among power levels from 2,500 lumens down to 300 lumens. Just in front of the switch is the Smart Dashboard: a multicolored three-light indicator that displays power settings and battery level. The switch twists to lock in the off position for safe travel. Charging the factory-sealed Li-ion battery is as simple as plugging the charger into the external socket. Surprisingly compact considering its impressive light output, the Sola is barely 4 inches long. On high power, the battery will give you nearly an hour; on more practical settings, it burns for two to four hours, and it charges fully from complete discharge in about 1 1/2 hours. Ruggedly built with a metal lighthead, it’s fully sealed and waterproof to 100 meters. We tried it with the optional nylon-and-neoprene hand mount, which is comfortable and secure; a pistol grip and T grip also are available. $700; lightandmotion.com

7. Sherwood Scuba Vision

If you’re dropping into the ink-black ocean after the sun goes down, it’s a good idea to keep your gear simple and streamlined. Sherwood’s Vision helps you do that by combining your computer, pressure gauge and compass in one compact dive instrument. The Vision’s dive display has large, bold characters and a clean layout for easy, at-a-glance reading. The three-button control is thoroughly intuitive, making for easy menu navigation and quick selections for nitrox, screen preferences and other settings. The backlight illuminates the screen with a warm glow that doesn’t hurt your night vision, and the compass and alternate dive data screens are easy to access throughout the dive. The Vision has a detailed menu with programmable audible alarms to alert you to you a selection of data, including depth, tank pressure, elapsed dive time, turnaround time and dive time remaining. It also lets you customize the display by selecting some of the data shown on the main dive screen. The Vision also comes with a locking quick-disconnect so it’s easy to pull off your reg when you’re ready to download your dive data to a PC. $920; sherwoodscuba.com

Night-Diving Tip

All geared up and nowhere to go? Check out our list of the best places for night diving.