The Fitting Saver® Repair System 4", commonly known as the Frankenplug®, is a fast, permanent solution for sealing underground pool return-line leaks—without digging, cutting concrete, or replacing plumbing. Designed for standard 1.5" pool return fittings, this innovative repair plug installs directly from inside the pool wall and seals leaks in seconds.

Once inserted into a cracked, stripped, or broken return fitting, the Frankenplug expands to create a dual seal—one in the fitting threads and another deeper in the pipe beyond the break. A built-in ¾" flow-through tube restores circulation immediately, allowing the pool system to remain operational right away.

Trusted by pool professionals, the 4" Frankenplug is ideal for most common underground return-line failures and is engineered for long-term, submerged use.

Fast, Reliable Repair

• Insert, tighten, and seal—most installs take under 15 seconds

• No excavation, deck removal, or plumbing replacement

• Ideal for emergency leak repairs during the swim season

Dual-Seal, Long-Term Fix

• Expands to seal both fitting threads and downstream pipe

• Designed for cracked, broken, or stripped underground return fittings

• Maintains full system circulation through the internal passage

Where It’s Used

• Underground return fittings on 1.5" PVC pool plumbing

• Common residential and commercial pool return lines

Key Features

• 4" overall length (standard repair depth)

• Repairs typical underground leaks in seconds

• Dual-seal expansion design

• 0.75" internal flow-through passage

• Simple, tool-assisted tightening for a secure fit

How to Use

1. Locate the failed return fitting at the pool wall.

2. Insert the Frankenplug fully into the damaged fitting.

3. Tighten until snug to expand the seals.

4. Confirm water flow through the ¾" passage and check for leaks.

The Fitting Saver® Frankenplug® 4" delivers one of the fastest and most effective underground pool plumbing repairs available—saving time, money, and major disruption.