These are very useful when trying to make lithophanes.

I really like the dimming and power off by touch function for this USB LED Lights, however, it does get pretty hot if use at 80-100% power. I cant really say these USB LED lights will last very long if continuous usage, they do use a fair bit of power when compare to another of the similar type.These Yitee give off yellow warm light even though they didn't say so in the details, so it arguable which is better/prefer but for high power bright usb light I think the warmer light is better for most ppl eye due to the fact most home lights are yellow warm lights.Would have given it a 5 stars if it didn't get so hot and use a bit more of power. Oh one last thing the touch function gets touchy, what I mean is it get activated no matter where you hold it. Like all things with dimming function which use far less energy when set to the lowest setting but your not gonna get much light from it either. The up side it can provide you with a tiny light at least when the battery is low which can be a power/Life saver for the long run.To compare I also brought before the Yitee brand, sure they don't have dimming or off function but they consume only 0.07 mha @ full power and even brighter than the Yitee which use 0.19 mha @ max, they both gets so bright it really can blind you. As such, all thing HIGH Power and Blinding Bright do not look at the light directly.

An extremely useful, versatile accessory. Very compact & robustly packaged, reasonably priced, powered by any standard USB interface. Useful as a utility light for a computer, or can be plugged into an AC USB adapter to serve as a night light, or into a keychain USB charger to serve as an impromptu area light or flood-type flashlight. Simply touch copper pad to turn on, and terminate contact when desired brightness level is reached. Touch again to turn off. Can be mounted with LEDs facing up for direct illumination, or facing down for diffuse indirect lighting. Has a very wide range of luminous output, uses very little power, and has a pleasant, comfortable "warm" spectral distribution. I have only used the item for a few weeks now, and it has functioned flawlessly, but am curious to know how well it will perform in the long term. Stay tuned for updates.

11-26-18, updated comments:Came back to order more for this Christmas. I have been running a few these lights CONTINUOUSLY for over 2 years! My in-laws came to live with us and we left these plugged in for night use. Father in-law is always getting up in the middle of the night and these provide good lighting. We use old wall chargers so the light is not blinding since they are low to the floor standard wall electrical outlets. No damage to the chargers or these little lights.I do keep one on my key chain for use in the car or emergencies. I have damaged 2 of these to the point they do not work. I test them every now and then. Carrying them on your key chain will eventually damage the devices. I have since started using thin-walled heat shrink tubing as a way to protect the circuitry. Even without it, the damaged units both lasted over 1 year on my key chain before dying.Original Review:Love these little light sticks! I came back to this product page to order more for myself and for others as stocking stuffers. As one other reviewer mentioned, I also use a lipstick type power bank as the power source lasts for hours! The lights are bright enough to use as a desk light for lighting. The ability to dim or brighten the light is fantastic. It can be turned down enough to use in bed or on a flight without being too bright for those next to you. Too low and some power banks will turn off due to the power bank thinking the device is fully charged since it uses so little power. I would guess that the light will last about 4 hours per 1000 mAh (if not longer per 1000. The lights do get fairly hot to the touch so be aware when touching the light to turn it off or down after it has been on a brighter setting for a while. Keep one of these in my travel "power kit" for emergencies. I also HIGHLY recommend getting a USB adapter that swivels or at least can be angled.For lighting a tent use this linked product: https://www.amazon.com/gp/product/B00QX096L0/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1These three products are ALL you need for COMPACT and very energy efficient lighting, especially for camping, travel, and emergencies!!!

While I could simply use my phone's LED flash as a flashlight, the reality is such LEDs are meant to be used as a camera flash strobe. There is no room to dissipate the heat generated by the LED, so when it's left on for an extended time period, the light itself would be shut off to prevent overheating. As the primary purpose of a flashlight is a light source, having it shut off - while still having ample power available - is not a desirable "feature". These LED "sticks", coupled with a USB OTG adapter, allow me to use my phone as a flashlight - without the overheating.As the instructions are a bit unclear, this is how the sticks work:- Insert the stick into the USB port. Note, it has contacts on both sides of the stick, so you can have the LEDs shine away from you.- The light does not turn on when you insert the stick, or re-insert after a removal. To turn it on, do a LONG TAP on the reverse side of the LEDs.- After it's turned on, a LONG TAP adjusts the light intensity.- A SHORT TAP turns the LEDs off - to turn it back on, do a LONG TAP.- The light intensity is kept in memory as long as the stick itself stays in the USB port. If the power is removed from the port at any time (either from physically removing the stick or power loss), the intensity setting is lost and it defaults to the brightest setting.- The lowest setting produces a very small amount of light and is safe to stare at with your eyes. At all other settings, the light intensity should be treated no differently than conventional LED flashlights - do not stare directly at the light.The power consumption of the stick depends on the light intensity. Using a PortaPow USB Power Monitor, the lowest setting registered less than 10mA of current (my monitor can detect up to two decimal places only), while the brightest setting is about 250mA. As it's well below the standard USB power specification of 500mA, these sticks can be used in almost any USB port - just remember that it doesn't turn on right away.Compared to the 3 LED sticks (http://www.amazon.com/gp/product/B00LUTGWBG/), which I also have:- the 6 LED sticks are dimmable anywhere between 50mW and 1250mW, while the 3 LED sticks always shine at their default 500mW setting- the 6 LED sticks need to be turned on at first with a long tap, while the 3 LED sticks turn on as soon as they're inserted into the USB port- the 3 LED sticks are shorter by a full USB port depthThe one disadvantage these sticks have vs conventional flashlights is lack of focus. The light projected is omni-directional, so a DIY reflector is required to make it shine in one direction.Pairing one of these 6 LED sticks with a lipstick-style external battery pack creates a rechargeable (and dimmable!) USB flashlight. As such, it's better than the LED flashlights built into many battery packs these days, because these are user-dimmable. Likewise, pairing this with a USB OTG adapter creates a flashlight that is powered by an Android phone, but without the overheating issues or privacy concerns associated with most flashlight apps.Highly recommended.