You might look here:<br><br>http://www.magnifyingglasses.co.uk <br><br>I found the site with www.google.com by searching on "fresnel lens magnifier uk" (without the quotes). There are probably more sites in the UK. I also suggest checking bookstores and stationery shops. <br><br>I carry a credit card sized lens in my wallet and a lens the size of a sheet of typing paper in a backpack in my vehicle. I bought both at an office supply store. I never thought about the magnification of the lesnes. I think any of them will work for starting fires. <br><br>I know I'm overstating the obvious here but in my opinion the fresnel lens is useful only when conditions are good- dry and sunny. Using the lens to start a fire saves your matches or lighter fuel. No matter how many matches you might carry, you don't have an endless supply. The fresnel lens is just one more firemaking tool, and you should ALWAYS carry other means of making fire. <br><br>If I had to give up one of my firemaking tools, the fresnel lens would probably be the first to go. (My ferrocerium rods would be the last to go. Thanks, Bagheera!) <br><br>When I first experimented with a magnifying lens I tried to light a single piece of dry grass. No luck. By experimenting I discovered the following technique. Gather a large handful of dry tinder and break it up by twisting it. This breaks down the outer surface of the stems and exposes the interior portion. It also creates more surface area. The preparation of the tinder is important with any firestarting method. Next, shine the light into the center of mass of tinder, focusing the beam of light not on the surface, but down into the tinder. I think that this helps to trap the heat. The tinder will heat up and begin to smoke, then burst into flames. Try not to stare at it as the light is very bright. Blowing on the tinder when it begins to smoke might help. The main thing is to experiment and find out what works for you. You might also experiment under varying light conditions- cloudy days, late in the day, etc. I have not done this myself, but I should. <br><br>The headlights (headlamps) on newer cars have fresnel lenses to magnify the light output. However, I don't know if one could separate the fresnel portion without destroying it. Also lenses from binoculars, camera lenses, etc have reportedly been used to make fire, but I have never attempted these techniques. <br><br>If you are a smoker the fresnel lens lights cigarettes easily (in strong light, of course), saving your matches or lighter. <br><br>Good luck!<br>