(?) "Complete" fixtures include both the Trim Kit and the required Rough-in Valve necessary for installation. The valve is the part that installs in your deck or wall and connects to the hot and cold water lines in your home. A "Trim Kit" is great if you already have the valve and just need the part you see (the trim).
The Concord Collection is the most popular of the modern designs. The emphasis here is that less really is more. Sleek cylindrical handles meet smooth cylindric faucet bodies creating a breathtaking effect.