Expanding on the F500 series design, the upgraded SP models use refinements taken from the F700 series, in the more basic cabinets of the F500 series (same size and shape but with a higher density fiberboard and improved internal dampening). The drive units and crossovers are based on the more costly F700 models with improved bass/mid-bass drivers, magnesium compression dome tweeter and the machined aluminum plinth design of their more expensive brethren. These speakers are designed, built, hand finished and pair matched in their UK factory. The result of this combination is a speaker that approaches the sound of the F700 series for about half the price. Finishes for the cabinets are also a cut above the standard models with beautiful Piano Gloss Black or Piano Gloss White finishes as standard and a Piano Gloss Walnut finish as an available upgrade.