Here's a little more information about each of the items included in the Porter Cable 7424 XP Starter 3" Kit. You can click the link to visit the product page for a full description:
Porter Cable 7424 XP Random Orbital Buffer - the most popular random orbital polisher amongst enthusiasts and professionals alike
Lake Country Dual Action (DA) Backing Plate (3") - the perfect backing plate to use with your Dual-Action Polishers
Lake Country White Polishing Pad (3.5") - helps safely remove minor surface imperfections such as very fine swirls, oxidation, etc.
Lake Country Orange Light Cutting Pad (3.5") - a light cutting pad designed to remove moderate swirls and scratches with a medium polish
Lake Country Black Finishing Pad (3.5") - a finishing pad is designed to bring the paint to its maximum depth and gloss when combined with a finishing polish
Lake Country Snappy Clean Boost Pad Cleaner - a citrus degreaser designed to help release product and contamination from foam pads