The Korg M1 MSC-6S Fretted Instruments 1 PCM Program Memory Cards are collectible items that provide additional program memory for the Korg M1 synthesizer. These memory cards contain preprogrammed sounds and tones for fretted instruments, allowing users to expand the capabilities of their synthesizer and access a wider range of sounds. Perfect for collectors and enthusiasts of vintage synthesizers, these memory cards offer a unique way to enhance and customize the sound of the Korg M1.