Therwen 3.5" Brass Sewer Cleanout Caps 2-Pack — Slotted Concave Threaded Plugs, Corrosion-Resistant

Therwen 2-pack 3.5-inch slotted brass sewer cleanout caps are durable, threaded concave plugs that seal 3.5" cleanouts and allow easy removal with a wrench or screwdriver.

If you need a reliable replacement for a 3.5-inch threaded cleanout on drain, waste, or vent piping, these slotted brass plugs provide a tight seal and simple access for maintenance. Made from machined brass with a countersunk head and square groove, each plug resists corrosion, installs quickly, and helps prevent leaks, odors, or debris from entering the plumbing system.

How do these cleanout caps fit 3.5-inch plumbing cleanouts?

The plugs are machined to match 3.5-inch threaded tubing and feature a countersunk (concave) head to sit flush with the pipe. The slotted top and square groove let you tighten or loosen the plug with common tools for a secure fit every time.

• Precisely sized for 3.5" threaded tubing and cleanouts
• Countersunk concave head ensures a low-profile, flush appearance
• Machine-cut thread for consistent engagement and leak reduction
• Square groove and slot accept standard wrenches and screwdrivers

What materials and design features make these plugs durable?

Each cap is fabricated from brass, chosen for its corrosion resistance and strength in wet or outdoor environments. The solid construction withstands repeated installations and exposure to wastewater, while the threaded design maintains a tight seal under typical service conditions.

• Heavy-duty brass resists rust and galvanic corrosion
• Precision threading reduces wear on the pipe connection
• Concave head minimizes surface contact and debris buildup
• Slotted and grooved top simplifies future removal and maintenance

Can I use these plugs for DIY repairs and professional plumbing jobs?

Yes — the Therwen brass cleanout plugs are suitable for both homeowner projects and professional use. They are straightforward to install, removing the need for special tools, and their reliable seal makes them appropriate for temporary or long-term applications in drains, vents, and waste lines.

• Pack of two provides a spare or allows servicing multiple cleanouts
• Quick installation with common tools like a flathead screwdriver or wrench
• Useful for new installs, replacements, or routine maintenance access
• Designed to keep out debris, odors, and vermin when properly seated

How do I install and remove the slotted brass cleanout caps?

Installation is straightforward: thread the plug into the cleanout until hand-tight, then use a wrench or screwdriver in the slotted head to finish. For removal, reverse the process; the slotted top and square groove provide purchase for tools even after long service periods.

• Thread in by hand, then tighten gently with a wrench or screwdriver
• Back out by turning counterclockwise using the slot or groove
• Use a sealant tape or pipe compound if a stronger leak-proof seal is needed
• Keep an extra cap on hand for quick replacement during maintenance

Who is this for: These Therwen 3.5-inch slotted brass cleanout plugs are ideal for homeowners, rental property managers, and professional plumbers who need a sturdy, easy-to-service cleanout cover. If you want corrosion-resistant hardware that fits standard 3.5" threaded cleanouts, offers a low-profile concave head, and can be operated with common tools, this 2-pack delivers reliable performance for routine plumbing maintenance and repairs.