HiLetgo 10pcs 5V 650nm 5mW Red Dot Laser Head Red Laser Diode Laser Tube with Leads Head Outer Diameter 6mm

These little guys are pretty decent laser diodes! They’re super bright and fairly inexpensive. I used three in a project for an ECE class at UCON and am very happy with the results. While I think they have a resistor built into the driver I’m driving them at about 4.5V with a 100Ω resistor in series with the device. The small package was easy to integrate into my project enclosure. I noticed that these are focusable. You can twist the collar near the output side to focus the dot. Yes, laser diodes don’t have a perfectly round dot, but when focused properly, you really can’t tell by eye over short distances. At 100 meters, you will definitely notice dispersion and distortion, but I very much expected that. All in all, these met my expectations, and I’m happy with how things turned out. They work great. Note: I only have a few hours of use on my project, so I can’t say how long they will last, but like most things electrical, you can pass a low amount of current through them for a long time or a very large amount of current through them for a very short time. If run at spec, I assume they will last just fine. BTW, I got an A on my laser transmitter project. W!

The price for this 10-piece set was fantastic, and the delivery was faster than I expected. I have not powered them all on yet, but I took a random sampling of 4 and they looked bright and uniform. The spot-size looked uniform in an 'across the room' test, so the laser quality seems fine. For my application, the "precision" of the aiming is done by hand, so I also wasn't too concerned if they are/not perfect in that regard. The lead wires would be a concern in an environment that experience much of any vibration, but that too was not a worry for my need, so I think they will be more than sufficiently durable. The size, of 5 mm diameter was easy to work with, and since I was 3D printing the holder, I could adapt to most anything. I also appreciated the option of either 3.3V or 5V, the latter of which was right for this project, but I also work with 3.3V designs, so I'll keep that in mind for the future.

These are Ok red lasers, but not for mission-critical projects. Some just die without warning, and you will need to replace them. I had a project with 32 lasers, two died before I installed them and 3rd one died later. But they are cheap and when they work - they work.

These diodes at 50 cents a piece are one heck of a bargain. To dispel some of the myths and reviews here is useful information. They only require a 5-volt power supply, that's it. I used an old desktop Christmas tree power/controller to power the diode, it Powers the diode quite nicely at 4.5 volts, and using the controller I get different beam options, (video attached) remember no driver boards or power modules needed, use batteries, 5 volt power supplies, (the diode will work at 3-5 volts although at 3v it's not that bright) THEY ARE FOCUSABLE ! I have seen complaints that they are out of focus, that's because the barrel of the diode is threaded, you can screw the forward portion of the diode barrel in and out to focus it at different distances, it is not one solid piece of brass but split in the middle. This is my second purchase of these, all have worked flawlessly and consistently. One caveat, the wiring is thin, as others have stated, they will break off at the solder joint quite easily. My suggestion cut down some electrical tape and wrap it around the board and wires to act as a strain relief, or, encapsulate the the board and wires with hot glue, this is the best way. Although not tested, my 40 years experience in lasers tells me these are hotter than a typical 5 MW laser diode.

It was a decent product; it works well for the price, but the lighting could vary depending on how good it was from one to another.

Works as advertised, pretty bright even in a well lit room I kinda wish I got green ones aswell

Good lasers for general use. Use a series resistor if you are driving from a higher voltage. Can be seen reflecting off a wall in daylight. Pretty bright.

Don't buy this. 10 lasers, only 4 work properly; the rest of them are misaligned, out of focus or both. Don't buy it. Unfortunately, I give it 1 star cause i can't give this garbage 0 stars.