FL17 & L18 Series Heavy Duty 3/0 AWG – 4/0 AWG Silicone Terminal Boots Fits M12+ Studs
P/N: FL17 & L18 Series
The FL17 & L18 Series fit extra-large wire diameters up to 17mm-18mm (approx. 3/0 AWG – 4/0 AWG) and accommodate massive battery lugs and mounting hardware.
Available in Rectangular (Square) and Extra-Large Round designs. Engineered for heavy industrial machinery, commercial trucks, and megawatt-scale power distribution.
Model Selection Specifications
| Model No. | Shape | Wire Entry | Cap Inner Dia. | Total Length | Features |
| FL17-20-30 | Rectangular / Square | 17mm (3/0-4/0 AWG) | 20mm x 30mm | 63 mm | Fits Flag Terminals |
| L18-25-76 | Standard Round | 18mm (3/0-4/0 AWG) | 25 mm | 76 mm | Large Cap (1 inch) |
| L18-35-94 | Extra Large Round | 18mm (3/0-4/0 AWG) | 35 mm | 94 mm | Huge Cap / Long Body |
Key Features & Benefits
- Heavy Duty Fit for 3/0 AWG – 4/0 AWG Cables
The 17mm-18mm wire entry is engineered for maximum current applications, creating a robust seal around thick gauge cables ranging from 3/0 AWG to 4/0 AWG. This heavy-duty sizing is essential for preventing shorts on main alternator feeds, starter motors, and industrial battery banks.
- Versatile Rectangular & Round Cap Designs
The rectangular cap of Model L17-20-30 (20x30mm) is specifically designed to fit “Flag” type terminals or rectangular busbar connections. The round models (L18-25-76 and L18-35-94) feature massive internal clearances (up to 35mm), perfect for covering large clamp-style terminals or multiple stacked lugs.
- High-Temp Flame Retardant Silicone Material
The flame-retardant silicone construction provides excellent thermal stability with a working temperature range of -40°C to +230°C. This durable material resists melting or cracking in high-heat engine bays and meets strict safety standards for commercial vehicles and heavy equipment.
- Extra Large Capacity for Industrial Hardware
The massive cap dimensions (up to 35mm ID) allow these boots to cover oversized mounting hardware, including M12 (1/2″) and M16 (5/8″) studs. This spacious design ensures complete insulation even for bulky, custom-made battery interconnects.
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Color-Coded for Safety & Identification
The Red and Black color options allow for clear visual identification of Positive (+) and Negative (-) polarity. This color coding is critical for safety in high-voltage industrial systems to prevent catastrophic reverse polarity accidents.
Application Gallery
Typical installation on industrial machinery and marine battery banks.
If you have any questions about the product or would like more information, we encourage you to contact us via email at sales1@chinadaier.com or through our live chat. We are here to help you and give you the information you need.