Sherwood ST1000 - 1000 Lumen Flashlight

Lumens measure the total light output, but they say nothing about how that light is shaped, so a tight narrow beam can look far brighter at distance than a higher-lumen wide beam. Beam angle, color temperature, and water clarity affect what you actually see as much as the lumen figure does. Use lumens to compare lights of a similar beam type rather than as a single score of quality.

A primary light is your main light, usually brighter, larger, and with a longer burn time, while a backup is a small, simple light carried in case the primary fails. Any dive where you need a light to exit safely, such as a night dive, calls for carrying at least one backup. Backups are chosen for reliability and simplicity rather than for maximum output.

Burn time and brightness trade directly against each other, so the same battery run at a lower power setting lasts substantially longer. Manufacturers usually quote burn time at each power level, and many lights automatically step down output as the battery drains or the head heats up. Treat quoted figures as fresh-battery, ideal-condition numbers and plan for more burn time than your dive actually needs.

The o-rings sealing the battery compartment are what keep the light from flooding, so inspect them for grit, hair, and nicks every time you open it, and wipe the sealing surfaces clean. Lubricate lightly with the grease type the manufacturer specifies, using a thin film rather than a heavy coat, because excess grease attracts sand. Replace o-rings when they look flattened, cracked, or dry, and do not over-tighten the cap in the hope of sealing a bad o-ring.

Lithium batteries are subject to airline and regulatory limits that vary by cell chemistry, watt-hour rating, and whether the cells are installed or loose. As a general rule lithium cells travel in carry-on baggage rather than checked baggage, with terminals protected against short circuit, but you must confirm your airline's current policy and any local rules before you fly. Carrying the manufacturer's battery specification sheet helps if you are questioned at screening.

Rinse it in fresh water after each dive day and work the switch while it is submerged so salt does not crystallize inside it, then dry it before opening. For storage, remove or charge the batteries as the manual directs, and leave the cap loose so the o-ring does not take a permanent set. Never store a light with corroded or leaking cells inside it.

Test it briefly as part of your pre-dive check, but do not leave a powerful light running in air, because many are designed to shed heat into the water and can overheat on the surface. Check the manual, as some lights have thermal protection that dims or shuts them down when they are dry. Testing before you gear up is far better than discovering a dead light at depth.

The ST1000 runs on an IT18650-A Li-Ion 2600 mAh cell, which Sherwood also lists as a replacement part.

The ST1000 offers four power levels: 100%, 50%, 25% and SOS Strobe. Published burn times are 1.0 hour at 100%, 2.0 hours at 50%, 4.25 hours at 25% and 3.5 hours on SOS Strobe, so the lower settings are the ones to use for longer dives. The three-color indicator shows green for full, yellow for half and red for low.

Yes, within recreational limits. It produces 1000 lumens in a tight 12° beam and is depth rated to 100 m / 328 ft, with 1.0 hour of run time at full output and 2.0 hours at 50%. The 6 in (15 cm) aircraft grade aluminum body is small enough to double as a travel or backup light, and it recharges through the integrated USB charger in 4 to 5 hours.

Each ST1000 ships with the flashlight, a padded case, the IT18650-A Li-Ion 2600 mAh battery, a charging cable and a braided lanyard. The ST1000 has a USB charger integrated in the unit and ships with a charging cable. Sherwood covers the light with a 1 year warranty against manufacturing defects. The light is published with CE and RoHS certificates and in a single configuration, with no color or size options.