Because they are really good skies, these arent your normal presets or random sky lab generations, alot of work went into making these. A good sky is hard to come by, it can make or break your image:). These are all made by personally selecting the skylab selectors one at a time and manually adjusting the cloud properties, from the amount of fog and haze to tweaking the frequencies until they looked just right. Feel free if you have the time to check out my gallery either here or on my site-chemicalstudios.com, and you can get a good idea of what you would be getting.:) Ken