Light stroller

What is the lightest stroller. I find that most strollers are very bulky and heavy. I would like to get a nice stroller that is not too heavy maybe one with an aluminium frame or something but I don't know which one is the lightest. Any ideas? Thanks.

I bought a Mclaren stroller which was very light. It lasted me through both my kids and a lot of abuse and after I was done with the stroller I was still able to sell it for a good ammount. The initial investment in a light stroller such as this one is higher than most other strollers but it is well worth the price.