US Part Number: 21261
Canada Part Number: N/A

Permatex® Bolt Mark™ Neon Yellow


Bolt Mark™ is a convenient visual method for identification of vibratory loosening or tampering in nuts, bolts, fasteners, and assemblies. This tamper-proof torque seal provides warranty protection against tampering. Marks will be easily broken if parts are tampered with or become loose and is highly visible under ambient light and fluorescent under UV light.

  • Versatile product use
  • Safe for most surfaces
  • Excellent adhesion
  • Risk mitigation against claims
  • Saves labor hours


Suggested Applications: Oil pan bolts, Belt tensioner bolts, Pulley bolt, Alternator mount bolts, Valve cover bolts, Heavy equipment bolts, Suspension bolts, Gear bolts, Transmission shaft bolts

US Item # CDN Item # Container Size Case
21261N/A6 mL tube 6
US Item # Tech Doc File
21261 TDS  SDS  


  1. Surfaces to be marked should be clean and dry before applying.
  2. Torque assembly to manufacturer specification.
  3. Apply a short, single line of Bolt Mark to desired area.
  4. Let material dry to touch before continuing with normal operation.
  5. High temperatures or hot air will cure product faster.
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