The Cable Tray Rubber End Cap is used to protect the engine wiring harness within the cable tray. It seals off the openings of the cable tray, preventing the ingress of dust, water, and other contaminants that could potentially damage the wiring and electrical components. 3M electrical end caps seal cable ends, providing reliable protection from environmental damage Which End Cap should I choose? Provides quicker and easier installation by unwinding the removable core. Package Quantity: 2, Sold in pairs. Category: Cable Tray Ends End Cap, 1-1/4", 2-Piece, PVC, Office White, 10 Individual/bag Category: Cable Tray Ends End Cap, 3/4", 2-Piece, PVC, Office White, 10 Individual/bag Category: Cable. Quest offers rubber end caps for covering terminated/jagged cut ends of cable tray. Accessories, mesh cable trays - End caps.