All Spruce & Rosewood Series feature Solid Spruce tops for the ultimate in tone, volume, and sustain. The backs and sides are made of Rosewood. The Boulder Creek exclusive "Dual Port System" is also standard on all of these models. Die cast tuning machines are also standard. All Acoustic Electric versions also feature the Boulder Creek UK-300T preamp and pickup system with built-in tuner. All Spruce & Rosewood models also feature abalone binding around the body and both soundports. The incredible finish and detail work on these fine instruments is second to none. There are lots of ukuleles on the market, and then there's the Boulder Creek Riptide Series. You decide.