Union Slide and Hull: a feature of the various saddles is the way the slide is coupled to the hull.
This can be coupled directly to the hull, creating a union stiff and light, but a lot of vibration transferred to the saddle, or by the interposition of elastomers, various forms and types, which filter the vibrations, improving comfort. The latter option is more expensive, making the seat slightly heavier. The slides are usually linked to carbon bonded to the hull to turn carbon (the best), but might include carbon skids that have joined the excavation no carbon, or a rigid or through the interposition of elastomers. This solution has the sole reason for being content to keep the price of the saddle, for technical purposes it is better to have a full carbon fiber seat (slide and hull).
The choice of union Slide and Hull: is one of those items where you can see the quality of a product. Saddles in the economic union is very rough and cheap, but far more sophisticated and high-end ones. If you have problems contact your comfort is good on those associations which provide for the interposition of elastomers, giving up a few grams less weight. In this case, however, the best result is obtained in sled hull carbon. The comfort level is combined with a sledge elastomers to the hull and the weight is much lower.