These lights have very easy to use mountings, and additional belt clips for when you're not using them on the bike mountings (though how useful that is, I'm not sure). Both lights are principally the same except that one has a red plastic cover, and the other is uncoloured. When they're flashing they're very good at drawing attention to you on the road. Unfortunately, the clear one (the front light) couldn't illuminate its way out of a paper bag when it's set to its steady light mode. I could barely see the road in front of me on an unlit country lane, and I certainly couldn't see any distance in front (I could see maybe two metres, at a push). I will need something extra at the front now, and these lights will be consigned to flashing, which I think makes them a bit pricey.
On the packaging, hidden on the bottom of the box, it says "For UK Consumers - When used for cycling these lights should be used in conjunction with British Standard 6102/3 cycle lights," but of course you can't see that on the Amazon page...