Description
Download the manual: KR-S40 Manual
The KR-S40 recycles in 1.2 seconds — more than twice as fast as comparable compact strobes on the market. For shooting active marine life or multiple exposures per dive, recycle time matters more than flash count.
40 watt-seconds. Compact. Built for macro.
The KR-S40 is Kraken’s compact strobe — 40Ws in a 530g package that won’t throw off your buoyancy or dominate your rig. It uses a straight flash tube rather than a circular tube, which keeps the size down and is well-suited to macro work where close-subject distances mean even a narrow coverage angle lights the scene effectively. If you’re shooting nudis, critters, and reef macro, this is the right tool.
Manual-only operation — S1, S2, and Multi optical slave modes. 1.2-second recycle, ~500 flashes per charge on a single 21700 battery. The 300-lumen spot focus light (15°) gives you precise targeting for small subjects in low ambient conditions. Optional warming filter available.
Key Features:
- 40 Ws, Manual Only: 5 power levels (2 / 5 / 10 / 20 / 40 Ws). No TTL — predictable, repeatable exposure every shot.
- Fast Recycle: 1.2 seconds to full power — fast enough for active subjects and multi-exposure sequences.
- Compact and Lightweight: 530g on land, 200g underwater. Designed to keep your rig balanced without overpowering a compact camera setup.
- Straight Flash Tube: Keeps the size down — the right choice for macro work where you’re shooting close subjects and wide coverage matters less than compact form factor.
- 60°+ Coverage Angle: Well suited to macro and mid-range subjects. Pair two for wide-angle coverage if needed.
- S1 / S2 / Multi Optical Slave: Syncs optically with your camera’s built-in flash or a master strobe. No TTL.
- 300-Lumen Spot Focus Light: 15° beam, 2 levels. Useful for precise focus on small subjects in low ambient light.
- Single 21700 Battery: 4000mAh, USB-C rechargeable. ~500 flashes at full power.
- Available in Pink, Seafoam, and Silver — colour options to match your housing or rig.
Technical Specs:
- Power: 40 Ws
- Color Temperature: 6000K
- Guide Number: 16 (1m, ISO 100)
- Coverage Angle: 60°+
- Recycle Time: 1.2 sec to full power
- Power Levels: 5 (2 / 5 / 10 / 20 / 40 Ws)
- Flashes at Full Power: ~500
- Battery: 1x 21700 (4000mAh), USB-C rechargeable
- Focus Light: 300 lumens, 15° spot, 2 levels
- Sync Modes: S1 / S2 / Multi optical slave (manual only, no TTL)
- Depth Rating: 100m / 330ft
- Dimensions: 62mm x 63mm x 130mm
- Weight: 530g (land) / 200g (underwater)
Accessories:
- KR-SN08 Optical Snoot for KR-S40 — precision spot lighting for macro and creative shots
- 4500K Diffuser for KR-S40 — shifts colour temperature for warmer, more natural tones on portraits and coral
- FT06 Colour Filters — creative colour gels compatible with Kraken snoots
- RC02 Remote Control — connects via fiber optic cable and lets you adjust power on two strobes simultaneously or independently, right from your camera tray. No reaching out along the arms to dial in exposure mid-dive.
- High Drain 21700 Battery — spare cell for multi-dive days
Further Reading
Best Underwater Strobes for Compact Cameras 2026
TG-6, TG-7, or RX100? How to choose between the KR-S40 and S80 based on what you shoot and how you shoot it.










