SYLVANIA 64978 | MC39TF/U/GU6.5/930 METALARC® POWERBALL® 39W Ceramic Metal Halide Lamp

The Sylvania 64978 (MC39TF/U/GU6.5/930) is a commercial-grade, high-efficiency **39W high-intensity discharge (HID) ceramic metal halide lamp** engineered for precision retail accent track systems, high-end museum vitrines, luxury hospitality spaces, and architectural highlighting. Outfitted with a specialized **GU6.5 twist-lock base** and an ultra-compact **T4 clear quartz glass profile**, this pulse-start module utilizes proprietary **POWERBALL® spherical arc tube technology** to project a vibrant, texturizing **3000K Warm White** light. Delivering a premium **90 CRI** color accuracy rating and producing **3,600 initial lumens** of high-efficacy light, it features an extended **15,000-hour rated service life**. Built with integrated **UV-Stop quartz glass** and certified for a **universal burning position**, this sub-miniature light source keeps color temperature shift tightly managed across its operational lifecycle.

POWERBALL® Spherical Technology and Twist-Lock Stability

Sylvania METALARC® POWERBALL® lamps utilize an advanced spherical ceramic arc tube geometry that ensures ideal thermal distribution within the discharge chamber. By eliminating the sharp corners found in standard cylindrical discharge elements, the rounded ceramic core reduces cold spots and minimizes chemical reactions over time. This architectural refinement limits color temperature shift to a precise **±150K** over its lifespan, maintaining stable light quality across adjacent fixtures. Paired with a rugged **GU6.5 twist-lock base** system, this lamp ensures positive electrical contact and secure structural seating, making it highly resistant to structural vibrations within modern retail tracking layouts.

• Universal Burning Orientation: Engineered to run seamlessly at any physical mounting angle or tilt path without impacting arc behavior, lumen output, or service safety.
• Integrated UV-Stop Barrier: Crafted with specialized UV-filtering quartz glass to block harsh ultraviolet wavelengths, helping protect high-end fabrics and delicate displays from fading.
• Elite Color Presentation: Delivers a balanced **90 CRI baseline**, revealing true color tones and casting a warm, premium atmosphere across commercial settings.
• Advanced Pulse Start Performance: Promotes rapid warm-up ignition times, consistent hot-restrike intervals, and high lumen maintenance throughout its **15,000-hour** rated service life.

Comprehensive Technical Specifications

• Brand Name: Sylvania
• Product Family / Series: METALARC® POWERBALL® Ceramic Series
• Ordering Code / NAED: 64978
• Technical Abbreviation Code: MC39TF/U/GU6.5/930
• Universal Product UPC: 046135649783
• Alternative Part References: 69044 (International Market Variant)
• Technology Type: High-Intensity Discharge (HID)
• Chemical Classification: Ceramic Metal Halide (CMH)
• Nominal Wattage: 39W
• ANSI System Circuit Code: C130/E (Enclosed Fixture Rated Only)
• Bulb Shape Configuration: T4 Clear Miniature Profile
• Base Type: GU6.5 (Specialized Bi-Pin Twist-Lock Interface)
• Initial Luminous Flux: 3,600 Lumens
• Luminous Efficacy: 92 lm/W
• Color Temperature: 3000K (Warm White Spectrum)
• Color Rendering Index (CRI): 90
• Color Stability Metric: Within ±150K across operational life
• Average Rated Service Life: 15,000 Hours
• Operating Burning Position: Universal (All mounting angles supported)
• Maximum Overall Length (MOL): 2.24 Inches (57 mm)
• Light Center Length (LCL): 1.38 Inches (35 mm)
• Bulb Envelope Diameter (DIA): 0.51 Inches (13 mm)
• UV Shielding Layer: Integrated UV-Stop Quartz Glass

System Integration, Ballast Matching & Operational Safety

• Mandatory Enclosed Fixture Protection (E-Rating): Operating under high internal pressures and elevated temperatures, this ceramic metal halide module **must exclusively be installed inside enclosed luminaires**. Host fixtures must feature a tempered safety glass lens to contain hot ceramic or quartz fragments safely in the rare event of an internal arc tube rupture.
• Ballast Synchronization Protocol: This module requires a matching, thermally protected electronic ballast built to **ANSI C130** standards. Sylvania recommends the **51989 (QTP1X39MH SM UNV J)** or **51990 (QTP1X39MH SM UNV F)** ballast platforms for optimal performance. High-voltage pulse start systems necessitate pairing this lamp exclusively with **4,000V pulse-rated GU6.5 sockets**.
• Ultraviolet Radiation Warning: This lamp can cause serious skin burns and eye irritation if the outer quartz envelope is broken, cracked, or punctured. Do not use where people will remain for more than a few minutes unless adequate shielding or safety interlocks are present. This bulb complies fully with FDA radiation performance standard 21 CFR Subchapter J in the USA and SOR/DORS/80-381 guidelines in Canada.
• Handling Safeguards: Always isolate primary building power at the circuit breaker before performing bulb replacement or fixture cleaning. Allow the lamp to cool for at least 15 minutes post-operation to avoid contact burns. Avoid handling the clear glass body with bare fingers; skin oils create thermal hotspots that can lead to early glass degradation.

Recommended Professional & Commercial Applications

• High-End Retail Track Lighting: Excellent for miniature spotlight tracks highlighting apparel displays, designer boutiques, and jewelry cases.
• Museum & Art Gallery Displays: Ideal for specialized vitrines, glass-enclosed shadowboxes, and targeted sculpture highlights requiring low UV output and exceptional color accuracy.
• Commercial Downlights & Accents: Well-suited for upscale hospitality reception spaces, architectural niches, and premium corporate corridors.