Internet says it best:

The Casio RAP-1 Rapman synthesizer keyboard is a compact powerhouse of musical creativity. Boasting 32 touch-sensitive keys and 25 preset tones, this keyboard delivers dynamic rap beats and melodies with ease. Explore a variety of musical styles with 30 rap pattern sound effects. Plus, elevate your performance with the scratch disk, offering four different scratch sounds, and three effect pads for added versatility. Whether you're a seasoned musician or just starting out, the Casio RAP-1 Rapman synthesizer keyboard empowers you to create and perform with precision and style.

This 32-key keyboard offers 25 preset tones, including piano, horns, guitar and sound effects; 30 Rap patterns, including rap, rock, house and more; a scratch disk that gives you control of up to four different scratch sounds by turning it with your hand, and three effect pads - three buttons on the console that give you one-touch access to a selection of exciting sound effects.

One of the best features of the Rapman is the Voice Effector function:  this changes the pitch of the sound being input through the microphone. 

The on board speaker is powerful enough for home use, but there's an 1/8" output too, for when you need to kick it up a notch.

This unit is in very good overall condition and 100% working condition. No leaks inside battery compartment and battery door is also included. Rapman can be powered either with five 1,5V batteries or external 7,5V PSU. Battery powering is also working on this unit as is the speaker. This sale only includes the unit, no PSU or microphone included.