Denisdeploeg offerts The Lee Betaplug® Expansion Plug, the most successful method to seal drilled holes for critical applications. The Lee Betaplug is a pre-assembled, one-piece, tapered expansion plug specifically engineered to seal fluid passages in metal castings and plastic housings leak-tight, without the use of threads or sealants. Controlled expansion during installation causes the lands and grooves on the O.D. of the plug body to bite into the wall of the fluid passage, creating a leak-tight seal and assuring retention. The unique tapered design eliminates the need for tight manufacturing tolerances, and allows the designer to minimize the wall thickness required around the plug, even for brittle housing materials. Note: Betaplugs are not recommended for use above 275°F (135°C).