(I) Core Definition & Key Features

Music greeting cards retain the fundamental form of traditional paper-based or rigid-card greetings (e.g., foldable, flat, 3D pop-up designs) while adding audio modules. Their key characteristics include:

1. Dual Expression Channels: Combine visual elements (handwritten notes, printed illustrations, photos) with auditory content (instrumental music, popular songs, custom voice recordings) to convey emotions more comprehensively.

2. Simple Trigger Mechanisms: No complex operations required—most activate music automatically when opened (via a pressure-sensitive switch) or manually when a small button is pressed; some high-end models support Bluetooth connection to play user-selected phone music.

3. Compact Audio Components: Equipped with miniaturized parts (micro-speakers, thin lithium batteries, memory chips) that are lightweight and unobtrusive, ensuring the card remains easy to carry and mail.

(II) Main Types by Music Customization

1. Pre-recorded Standard Type

The most common category, with fixed audio pre-installed during production. Typical options include:

◦ Festival-themed music (e.g., "Jingle Bells" for Christmas, "Happy Birthday" for birthdays, traditional folk tunes for Lunar New Year);

◦ Generic warm melodies (soft piano, violin pieces) suitable for general occasions like thank-you or get-well messages.

They are cost-effective, widely available in supermarkets, stationery stores, and online marketplaces (e.g., Amazon, Etsy), and ideal for quick, casual gifting.

1. Customizable Type

Designed for personalized needs, allowing users to modify audio content:

◦ Voice Recording Models: Feature a "record" button that lets senders record short messages (e.g., a personal greeting, a snippet of a sung song) directly onto the card, with playback duration usually ranging from 10 to 60 seconds;

◦ Music Downloadable Models: Support connecting to computers or smartphones via USB or Bluetooth to upload favorite songs, instrumental tracks, or even personalized playlists (common in premium brands like Hallmark’s "Sound Studio" series);