Review: Acebeam EC35 II (Killzone SST-20 edition)

This Acebeam EC35 II (SST-20) was provided by Killzone Flashlights for review. That's an affiliate link, and my affiliate coupon code "zakreviews" will get you 10% off most flashlights at Killzone.

I played a small role in the creation of this special edition by sugesting the use of the high-CRI SST-20.


The Acebeam EC35 II is a duty/tactical flashlight slim enough for pants pocket carry. This Killzone special edition uses a Luminus SST-20 LED with better color rendering, more throw, and less output than the Samsung LH351D used in the base model. Intensity (candela) or throw distance is often lacking in lights this size with higher output numbers, or only available briefly due to heat. It's almost never combined with good color rendering in duty-style flashlights.

With quick access to max output via the tailswitch and a selection of modes including sub-lumen moonlight available through the sideswitch, the EC35 II is suited to a range of situations from emergencies to use inside a darkened vehicle. The USB port even serves as a powerbank to charge other devices, though I find that function a bit out of place on a duty light. A rubber plug of reasonable quality seals the port when not in use, though it is not waterproof if the plug is removed.

Perhaps the biggest shortcoming in my review sample is the LED itself. My sample is unusually green, outside of ANSI white on lower modes. Color rendering measurements are also worse than the same emitter in other Acebeam lights. It is, however vastly better than the industry average for duty lights. The EC35 II SST-20 is recommended.


Spec -
Battery 1x18650, 2xCR123A
LED Luminus SST-20
Color temperature 4470 K
Color rendering index 92.1
Max output 720 lm
Max throw 223 m
Max sustainable output 444 lm
Max sustainable throw 175 m
Max output at 50% battery 642 lm
Best efficiency 101 lm/W @ 285 lm
Candela per lumen 17.3 (mildly throwy)
Length 139 mm
Head diameter 29 mm
Weight 85 g
Weight with battery 134 g
Charging USB-C (noncompliant)
Low Voltage Protection (LVP) Yes
Lockout Mechanical and electronic
Approximate price $77
Rating ★★★★☆ (4/5 recommended)


  • High CRI
  • High-only tailswitch for easy operation under stress
  • Good sustainable throw without overheating (for it size)
  • Good build quality
  • Fits and charges virtually any 18650 battery


  • Green tint
  • Not waterproof with USB flap open
  • Noncompliant USB-C charging requires A-C cable

Details and technical analysis


The EC35 II SST-20 only comes one way, though the bundled battery is optional. There is also a base model EC35 II with a low-CRI Samsung LH351D.


The EC35 II comes with a holster, user manual, USB cable, lanyard, spare O-rings and spare tailswitch cover. An 18650 battery is optional.

Modes and user interface

State Action Result
Off Click sideswitch Last used (except strobe, moonlight, turbo)
On Click sideswitch Off
Off Long-press sideswitch Moonlight
Any Double-click sideswitch Turbo
Any Triple-click sideswitch Strobe
Turbo Double-click sideswitch Last-used
Any Half-press tailswitch Turbo (momentary)
Any Full-press tailswitch Turbo (on)
Off Hold sideswitch 3s lockout
Lockout Hold sideswitch 3s Moonlight

Using the tailswitch overrides any mode chosen with the sideswitch other than lockout. Turning the tailswitch off always turns off the light.

Output, runtime, and efficiency

There are no official performance figures published for the SST-20 version of the EC35 II.

Mode Estimated Lumens Estimated throw (FL1 meters) Candela
Moonlight - -
Low 14 30 228
Medium 127 93 2152
High 285 139 4830
Turbo 720 223 12480
Mode Estimated lumens Minutes to 80% Minutes to 50% Minutes to 10% Efficiency (lm/W)
Medium 127 423 428 431 87
High 285 221 227 237 101
Turbo 720 4 104 123 80
Turbo (cooled) 720 40 63 91 70

Measuring current draw was not practical due to the nested-tube body design.


Light quality

Readings are taken from the center spot diffused with DC Fix diffusion film using an X-rite i1Pro spectrophotometer.

Mode Color Temperature Tint Duv CRI CRI R9 (deep red) CRI R12 (deep blue)
Moonlight 4478K 0.006155 (extremely green) 93.8 79.2 69.0
Low 4271K 0.007144 (extremely green) 93.3 75.3 69.5
Medium 4470K 0.006624 (extremely green) 92.1 69.0 70.9
High 4401K 0.005928 (very green) 91.2 67.7 73.3
Turbo 4666K 0.002981 (moderately green) 92.1 73.4 81.2

A Duv greater than +/- 0.006 is not white according to ANSI standards. Only turbo has tint I would describe as pleasant, and the change in that mode is as noticeable to the eye as the numbers suggest. CRI numbers are also a little bit disappointing for an SST-20, which usually has an Ra over 95 and R9 in the 90s. Other Acebeam lights using 4000K SST-20s such as the TK16 had much better tint and R9 numbers.

Despite that, the industry average is an Ra around 70 and a negative number for R9, so the EC35 compares favorably to most of its competition. The recent industry trend to use cool white Luminus SST-40s in similar lights makes the green tint seen here look mild.

There is a slight ripple in moonlight, but no PWM flicker in any mode.


EC35 vs Olight Warrior Mini 2 and Zebralight SC64c LE

EC35 vs Zebralight SC64c LE

Batteries and charging

The EC35 II can use virtually any 18650 battery. Protected, unprotected, protected with USB port, button-top, flat-top, and flat-top with a significant dent all work reliably. Shaking the the flashlight vigorously does not cause any battery to disconnect. 2xCR123A is compatible as a backup option.

All manufacturers should take note here. This is battery compatibility done right.

18650 batteries can be charged inside the light using a USB-C port, however a USB A-C cable must be used. The EC35 II can act as a USB powerbank, and can use a C-C cable to power another device at up to roughly 2A.

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