The Vredestein Latex tube is a lightweight champ at 49 grams. Between the weight and ride of the latex material it is almost guaranteed to improve your ride quality and bring you that much closer to cycling bliss. This comes with a price though. Durability. At alf the weight of standard tubes you can expect more frequent flatting from errant road debris and pinching of the tire casing. Air loss may be another concern. You will need to check and air up before every rising session as the latex losses air faster than butyl. The tubes are also un-patchable. Bottom line is, if you want lightweight and ride quality and your willing to do a little extra work to get it, these tubes may be a good choice.
This Vredestein Latex tube has a smooth valve stem and removable valve core. Vredestein calls the total valve length 60mm measured to the very tip. It is closer to a 52mm by other manufacturers. This length is perfect for most standard rims and also works well with the slightly deeper-sectioned rim used on the Mavic Ksyrium wheels.
I won't tell you about how you need to take care mounting these or how you need to pump them up every day - you probably know that already if you are looking at buying these.
What I will tell you is that I have found these to bring all of the benefits of latex ride quality and low weight with surprising durability. For the heck of it I left these on under a pair of Michelin Pro4's on some race wheels and rode my normal training rides as well as some backroad exploration to see how long they lasted. Over chip and seal and loose rocks/gravel and any other normal road hazard that you can think of, I went through nearly a month of both training and racing without a puncture. The flat I did have cut the sidewall of the tire and would have puntured any tube. These ultralights have proven to be an outstanding product when paired with the right tire.
Pros: Weight, durability, feel.