Seachoice RP-MP1336SC Stainless Steel Nylon Insert Locknut 5/16"-18

The Seachoice RP-MP1336SC is a corrosion-resistant stainless steel locknut featuring a nylon insert for superior vibration resistance. Designed for marine and outdoor applications where reliability is critical, this 5/16"-18 locknut prevents loosening in high-vibration environments common on boats, trailers, and marine equipment.

Key Features:

• Stainless steel construction resists corrosion in saltwater and harsh marine environments
• Nylon insert provides positive locking action to prevent backing off from vibration
• 5/16"-18 thread size fits standard bolts and threaded rods
• Reusable design maintains locking effectiveness through multiple installations
• Comes in convenient 4-piece bag for multiple repairs or installations

Nylon insert locknuts, also known as Nyloc nuts or elastic stop nuts, are essential fasteners for any marine toolkit. The nylon insert grips the bolt threads to create friction that resists loosening caused by vibration, thermal expansion, and movement—making them ideal for securing hardware, railings, cleats, and accessories on boats, PWCs, and marine trailers.