4" UNISEAL
Uniseals are used to attach pipe to just about any container in situation where bulkheads will not work.
The most common use is on curved surfaces such as storage drums, buckets, and even other pipe.4" Uniseal Specs:

Pipe ID - 4" (100mm)

Pipe OD - 4.5" (114mm)

Holesaw size: 5" (127mm)

Up to 3/8" Wall Thickness.
Made in the USA