MSD 3415 Numbered Cylinder Heat Shrink Sleeve Spark Plug Wire Markers

The MSD 3415 Numbered Shrink Sleeves are heat-shrink wire markers designed to keep your spark plug wires clearly identified at all times. Each sleeve slides over a spark plug boot or other wire connection and, when heat is applied, shrinks tightly around it for a secure, professional fit.

Printed with cylinder numbers 1 through 8, these sleeves eliminate any guesswork during engine work, making it fast and easy to identify each wire — especially critical during high-pressure pit stops or engine service. The black sleeves feature high-contrast white numbering for at-a-glance readability.

Key Features:

• Black sleeve with white cylinder numbers for easy identification
• Fits spark plug wires up to 9mm in diameter
• Compatible with 8mm to 8.8mm ignition wires
• Heat-shrink design creates a tight, secure fit over boots and connections
• Engineered to withstand high underhood temperatures without splitting
• Legal for use on emissions-controlled, non-emissions-controlled, and race-only vehicles
• UPC: 085132034154

MSD's numbered shrink sleeves are an easy, low-cost upgrade for any performance or racing build. Proper wire identification reduces installation errors and keeps your ignition system organized and reliable.