Improvements in lithium-ion battery technology have enabled compact flashlights to achieve significantly higher output levels and one example of these capabilities is the Streamlight MegaStream USB. Announced earlier this year at the 2025 SHOT show, this new light designed for everyday carry features a maximum output of 1,800 lumens, focused beam pattern with TIR optic, multiple output levels, and USB-C charging without having to remove the battery.
Key Specifications
- Output: 1,800 lumens high, 500 lumens medium, 150 lumens low
- Intensity: 26,000 candela
- Runtime: 2h high, 3h 30min medium, 13h low
- Battery: SL-B34 Lithium-Ion Rechargeable Battery Pack (3,500mAh)
- Length: 5.3″
- Diameter: 1.1″
- Weight with Batteries: 5.4 oz.
- Colors: Black
- Warranty: Limited Lifetime
- MSRP: $148
- Actual Pricing: ~$85
Pricing & Contents
Included in the paper box (item # 66210) are: Streamlight MegaStream USB, SL-B34 battery (installed), nylon holster, USB-C cable, and user manual.
Batteries
The MegaStream USB uses a 18650 size SL-B34 rechargeable lithium-ion battery with a capacity of 3,500mAh and built-in USB-C charging port. Compared to the existing SL-B26 currently used in other Streamlight USB rechargeable lights, the SL-B34 increased capacity from 2,600mAh to 3,500mAh and also replaced the Micro USB charging port with a more robust USB-C connector.
Charge time is 5 hours unless limited by the USB power supply. The charge indicator LED is on the top of the battery but a faint glow can be seen through the cutout for the USB-C charge port.
The Light
The MegaStream USB is has a length of 5.3” and is fairly compact for an 18650-based light. The aluminum body is type-II anodized and has a waterproof IPX7 rating.
Head
The head features a smooth bezel with a TIR optic.
Body
The charging sleeve is held in place by friction from the O-ring and does not have any threads. To ensure correct orientation for the USB-C charge port, the positive terminal on the SL-B34 is shaped with a flat side that slots into the head and prevents the battery from rotating.
Tail Cap
The pocket clip is attached to the tail cap, but like most of the ProTac and Stream lineup, it is not securely attached and can be pulled off with moderate force.
Textured black rubber with the Streamlight logo covers the forward click switch. The tail cap has a shallow shroud which neither protects against accidental activation nor allows the light to tail stand. However, the threads are anodized so the tail cap can be unscrewed a quarter turn to disable the light.
Modes
Three output levels can be activated using the tail switch.
High
Maximum output of 1,800 lumens.
Medium
Medium output of 500 lumens.
Low
Reduced power output of 150 lumens.
Performance
Using a Luminus SST-40 LED, the MegaStream USB uses the same emitter as the Strion 2020 which we recently reviewed. Both lights use TIR optics, though the one in the MegaStream USB has a smaller diameter which results in marginally lower peak beam intensity.
The beam pattern is clean with no visible shadows, dark spots, or edges.
Runtime
If you haven’t read our article about runtime graphs and the ANSI FL1 Standard, please click here.
Streamlight uses step-down regulation for high output mode to maintain a reasonable temperature and prevent overheating, but medium and low output modes are well regulated. The MegaStream USB gets rather warm to the touch after a couple minutes of continuous operation on high and the output is maintained at ~850 lumens for the remainder of the runtime.
Conclusion
The Streamlight MegaStream USB is a compact light with the output and runtime that one would usually expect from a mid-sized rechargeable such as a Strion or Stringer. As a member of the Streamlight Stream family, the MegaStream USB shares the same design elements from lights such as the MicroStream (which we reviewed all the way back in 2011!) including a smooth design with no knurling or sharp edges, making it pocket-friendly for everyday carry. For additional protection, the light can also be stored in the included nylon holster.
Having an impressive 1,800 lumen high output does come with a couple drawbacks for the MegaStream USB, especially in certain EDC type of scenarios. Unlike the ProTac series which has programmable function sets where the high/medium/low output order can be reversed to low/medium/high, the high output can be blinding at night or when working with items up close. Another potential issue is that the charging port cover can open by itself. This is particular prone to happening for users with larger hands while turning on the light. Keeping the O-ring dry and free of grease/lubricants does help mitigate the problem, but if the cover is accidentally opened, the water resistance rating is no longer applicable and electronics can get wet.
While there are a couple potential concerns with the Streamlight MegaStream USB, this compact rechargeable light does offer several unique benefits. Although the charging port cover introduces the risk of water ingress, it allows the battery to be recharged inside the light by plugging the USB-C cable directly into the battery without using an external charging port or charging contacts, both of which would increase the light’s length. However, the best feature of the MegaStream USB is the TIR optic, which despite the light’s small bezel diameter, produces a focused yet smooth beam pattern with 26,000 candela that is enough to compete with the output of many primary duty lights.
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Related Links
Streamlight MegaStream USB Product Page
