Slide-O-Mix has been one of the most popular handslide lubricant options available for decades, renown for providing fast and resistance-free performance.  The classic formula uses a main lubricant (the larger bottle) and silicon (the smaller bottle); when combined together on the slide (primarily the main lubricant and a few drops of the silicon) it offers one of the best slide lubricants on the market.  Many players find particular combinations of the two solutions that best fit their own instruments. 
 
Note: Slide-O-Mix tends to separate when exposed to extremes in temperature; keeping it at 50-75 degrees will help to prevent separation and keep it in ideal condition!