Over the years I have aquired an assortment of crampons but the ones I find the most useful and light to carry (just in case) are those that hit the market during the recent cold winters when people were buying them to walk down the street. I have a pair that you can pull on over anything from trainers to rigid boots and when you chance upon stretches of icy paths (like last weekend up on the South Pennines) they can be on and off in less than a minute. Okay, so you can usually find a walk around these patches but they just saves you the bother as they are unnoticeable on your feet between the stretches of ice. Invest wisely though. You will find some are incredibly cheap and only intented for the town pavements. I paid the better part of £40 for mine and have no qualms about wearing them on ordinary hill walks. I've better pairs for the serious stuff so I have no intention of testing them on anything more challenging than a icebound path just to make a point. Small and light - In winter they live in the rucksack with the other gear that is always in there.