Electrical Terminal Boot - MS-25171/ AA-59178

Silicone Rubber Terminal Boot for Electrical Connections

C & M Rubber Co. manufactures four sizes of electrical terminal boots used in products requiring a physical protective cover for electrical terminal posts. Originally designed and predominantly used in the aerospace market, these parts have proven to be a cost-effective off-the-shelf solution for a host of electrical connector applications such as marine batteries, hot tubs, gas-powered residential and farm equipment, and electronic telephone switches to name just a few.

Using rubber silicone Class II, 50 Duro (Shore A) per MIL-R-5847, the terminal boot is manufactured using liquid injection molding (LIM) systems. They are then batch processed in a cryogenic de-flashing system to yield a “whistle clean” finish. Visual in-process and post-process inspections are used to ensure your delivered parts meet Mil-Spec AA-59178 (superseded MS-25171 Mil-Spec).

These terminal boots tolerate temperatures from -85 to 401°F and are resistant to environmental exposure. C & M Rubber manufactures these terminal boots in four standard sizes and certifies them to AA-59178-1, -2, -3, and -4 standards (detailed below). The standard color is white, however, they can be specified in black and brick red. Lead-time for standard colors in quantities less than 20,000 pieces is typically 3 weeks or sooner (ARO) depending upon current in-house order cue. Custom colors are also available at a minimum upcharge and a slightly longer lead-time depending on quantity and schedule requirements. For more information on these silicone terminal boots or a custom designed electrical terminal boot made specifically for your application, request a quote today.

Multi-Cavity LIM Molding Highlights

Product Name
Electrical Terminal Boot – MS-25171 & AA-59178
Product Description
These electrical terminal boots are used to protect and house electrical terminals.
Capabilities Applied/Processes
Primary: Multi-Cavity Liquid Injection Molding
Secondary: Cryogenic De-Flashing
Equipment Used to Manufacture Part
22 Ton BOY LIM Unit
Overall Part Dimensions
F – Diameter: 0.16″
Nearest AWG Gauge: 6
Conductor Diameter: 0.1620″
Turns of Wire per Inch: 6.17
Copper Resistance: 1.296 Omega/km
F – Diameter: 0.43″
Nearest AWG Gauge: 000
Conductor Diameter: 0.4096″
Turns of Wire per Inch: 2.44
Copper Resistance: 0.2028 Omega/km
F – Diameter: 0.31″
Nearest AWG Gauge: 1
Conductor Diameter: 0.2893″
Turns of Wire per Inch: 3.46
Copper Resistance: 0.4066 Omega/km
F – Diameter: 0.56″
Nearest AWG Gauge: 0000
Conductor Diameter: 0.4600″
Turns of Wire per Inch: 2.17
Copper Resistance: 0.1608 Omega/km
Tightest Tolerances
Certified to New AA-59178 and Outdated MS-25171 Spec
Material Used
Rubber Silicone Class II, 50 Duro (Shore A) per MIL-R-5847
Material Finish
Standard Colors
  • White
  • Brick Red
  • Black
Optional Colors (Additional Cost)
  • Orange
  • Bright Orange
  • Bright Red
  • Yellow
  • Blue (Fluorosilicone Only)
In Process Testing/Inspection Performed
Visual In Process
Post Process Inspection
Withstand Temps From -85 to 401°F
Resistant to Deterioration by Weathering
Industry for Use
Delivery/Turnaround Time
Stock and Manufactured to Order – 3 Days to 30 Days
ARO Based Upon In-House Order Cue
Delivery Location
Standards Met
Customer Specifications
2D CAD Drawing
AA-59178 Commercial Item Description (CID)