OLight SR51

Battery: 6xCR123A or RCR123A or 2×18650
High Mode: 900 Lumens – 110 minutes
Low Mode: 250 Lumens – 10 hrs
Strobe Mode: 10 HZ
Water Resistant to IPX-8
Reverse Polarity Protection
Super Strong Anti Reflex Coated Lens
99% effective transmission
Dimension: 63mm (2.48in) x 190mm (7.48in)
Weight: 400g (without batteries)
Stainless Steel Bezel
Aluminum Body with Type-III Anodizing

First Impressions:
Another great packaged light from Olight arrived for review in its padded hard shell case. Has the same look and feel as the other Olights I have reviewed, except this time in a smaller form factor. Some may not care to store the light in its provided case, but I think its a nice touch, besides you would always use the case for something else.

The SR51 surprised me the other day when I picked it up, I thought I didn’t have any batteries in it, hit the switch, and it lit up! Turns out I had a pair of 18650 cells already loaded, its much lighter than it looks. The size is spot on for a light of this purpose and output.

   The SR51 has the same body style as the other Olights with its large rectangular knurling. I think its a nice choice for a light this size compared to a typical fine knurling. Provides plenty of grip without feeling rough in your hand. The side switch is great also, every light this size or larger should have a side switch, I find it much easier to operate than a tail switch on a light this size. This also allows the light to tailstand since there is no tail switch. I find this to be a big plus for a light like this. I found myself lighting up a room several times by sitting the light on the table bouncing the light off the ceiling. The light is also well balanced in your hand, the side switch is also in a good position and has a good feel to it, with a decent click when it is pressed.

Build Quality:
The build quality of the SR51 is on par with the other Olights I have seen, good even finish, smooth machining. The reflector and lens are dust free, and the led is well centered. The battery carries are very well made also and slide into the body of the light with little to no play.

One of the cool features I noticed about the SR51 is that the red oring seal for the lens, which looks great already, will actually glow in the dark! The SR51 was also supplied with a diffuser lens cover that works VERY well. It makes a very smooth even flood of light which lit up an entire room perfectly. Really makes the light that much more useful and versatile, since without the diffuser the light has some really good long distance throw.
One feature that I am not sure that the older Olights had, is the ability to lock out the light. The SR51 has this feature and I think its a very useful addition. When the light is on, you press and hold the switch to cycle between the lights two output levels. If you hold the switch for about 3 seconds, the light will cycle back and forth about 3 times, then turn off. The light is now locked out, and pressing the switch will not activate it. This is great for being able to just toss the light into a backpack and not care. To unlock the light you press the switch 3 times within a second.
The SR51 also has a hidden strobe function. When the light is on, simply double click the switch quickly.

Output & Runtime:
    The SR51 packs alot of punch for its relatively small size. The light orange pealed reflector is perfect for this led. It makes a nice tight hotspot with a nice perfectly smooth flood. There are virtually no rings or artifacts around the hotspot. I did notice that the hotspot was a warm tint with the remaining flood being quite white. At first this was a bit odd with that much tiny variation in the beam, but I actually light it alot after using it. I generally like a very white tint, but a warm tint has better color retention. The warmer hotspot created a much more natural light which especially looked great outdoors. The difference in tint really isn’t all that noticeable when shinning the light at t distance and was not irritating at all. Again, for a light of this purpose, and this output, I found the SR51 to have one of the best beam patterns I have ever seen.
My one complaint about this light? The fact that it only has two output levels. This comes down alot to personal preference, but I light my lights to have alot of output levels so I can choose just he right level for the situation. I just feel that the SR51 could be even more useful and versatile if it had at least 4 or 5 levels, especially if the lowest was quite low. This would give the SR51 a killer runtime on low, and could be used in tailstand mode to light up a small room for days if you are in a power outage. I am such a stickler for output levels, that its the one thing that is stopping me from ordering one of these lights for myself… actually, I am going to buy one anyway.

Heat Issues:
I had the light on for at least 10 minutes with the diffuser on, tailstanding on a table. When I picked up the light the head was getting warm but not uncomfortable to hold at all and not nearly hot enough to hurt the led. I don’t see why there would be any heat issues with the SR51, there is plenty of head and body mass to dissipate the heat.

Excellent beam pattern with no artifacts
Easy to operate side switch
Comes with a nice padded hard case
Diffuser is a great included accessory
Able to tailstand
Light weight for its size
Able to run off 6×123 cells or 2×18650 cells

Only two output levels
Warmer tint to the hotspot compared the cool tinted flood

Even though the SR51 is not the most powerful Olight, I still think it might be my favorite. Sure there are lights out there that have a higher output and throw even further than the SR51, such as Olights larger lights the SR90 and SR91. But if you are looking for a relatively small light that packs a great punch of usable light, the SR51 is certainly one to look into. Compared to other lights in the 800 to 1200 lumen range, I think the SR51 is probably my overall favorite. Even though it only has two output levels, and may not be quite as bright as some of the others, it still seems to be the overall winner when everything is considered, especially price and bang for buck. The SR90 and SR91 are amazing lights, don’t get me wrong, but unless you really need that kind of output, you really give up usability with a much larger heavier light, and pay higher price, mainly due to the rechargeable packs they use instead of separate cells.