Key Features:
1. Multiple insulated conductors (2-24 or more)
2. Color-coded or numbered conductors for identification
3. Outer sheath protects against environmental factors
4. Flexible or rigid construction
5. Various materials (copper, aluminum, fiber optics)

Applications:

1. Industrial control systems
2. Power distribution
3. Telecommunications
4. Data transmission
5. Audio/video installations
6. Medical equipment
7. Aerospace and defense

Types of Multi-Core Cables:
1. Power Cables (e.g., 3-core, 4-core, 5-core)
2. Control Cables (e.g., 2-core, 4-core, 8-core)
3. Signal Cables (e.g., audio, video, data)
4. Fiber Optic Cables (multi-core or multi-fiber)
5. Hybrid Cables (combine power, control, and signal conductors)

Benefits:
1. Space-saving
2. Reduced installation time
3. Improved organization
4. Enhanced safety
5. Increased reliability

Specifications:
1. Conductor size (AWG or mm²)
2. Insulation material (PVC, XLPE, etc.)
3. Outer sheath material (PVC, PE, etc.)
4. Temperature rating
5. Voltage rating
6. Frequency range

Standards and Certifications:
1. IEC (International Electrotechnical Commission)
2. UL (Underwriters Laboratories)
3. CE (Conformité Européene)
4. RoHS (Restriction of Hazardous Substances)

When selecting multi-core cables, consider factors like conductor size, insulation material, and outer sheath type to ensure compatibility with your application.