I have included a short, video demonstration of the Lenser LED 8313 K3 keyring torch. It shows the speed focus system in action on a wall from a distance of between 2-3 metres. The spot-to-flood feature can easily be operated one-handed. The white light from this little torch is amazing; you will be very pleasantly surprised by the powerful beam coming from this small and lightweight torch.
It sits comfortably on my key ring, together with my Leatherman Micra and all my keys. The torch is very robust and made from metal; it should withstand all but the most severe of punishments. I dropped mine on a hard floor from about a metre and it wasn't marked or scratched in any way. And yes, it still works! The power switch at the end of the barrel is very tactile indeed and so easy to use. I've been clicking it on and off just for the sheer joy of it. (I obviously need to get out more). The power button can be held and released if you need just a short burst of light, or you can press it in properly (without having to hold it in) for longer periods of light. There is a definite click action and it works very well. The design is such that it won't come on accidentally whilst on your key ring or inside your pocket.
When I first saw the key ring attachment, I was concerned that it would not be strong enough to withstand the day-to-day stresses of being attached to my key ring. However, it has proven to be stronger than it looks and I am confident it will stay attached to my key ring through normal, everyday use. For convenient removal, I have attached it using a removable clip so I can easily use it without all my keys dangling from it.
The included batteries can be quite fiddly to install. Rather than try to insert the batteries one at a time, I would suggest you pile the batteries up on the table and lower the torch onto them. This is far easier and quicker. The end of the torch screws securely on. One thing Amazon's description fails to point out is the fact that in addition to 4 x AG13 batteries, this torch will also take a single type N battery. (Also known as type 2011, LR1, KN or MN9100).
In summary, I would highly recommend this superb little torch. It is small and light enough to be carried on a key ring and for its size and price, it provides a very impressive coverage and intensity of clear, white light. This goes without saying, but I'm going to say it anyway: this is a small, key ring torch that costs under £10. It is not as powerful as the more expensive LED torches. But those torches are far too big and heavy to have on your key ring. Bear that in mind and you won't be at all disappointed.