Mastertrap Drain Rat Blocker Single Flap 4" / 100mm

Rats use drainage systems to move between properties and access buildings through toilet connections, floor drains, and wastewater pipes. This single-flap valve installs inside 4-inch (100mm) diameter drains to block that route permanently while maintaining normal water flow and drainage function.

The one-way flap mechanism allows rats already inside the system to exit but prevents re-entry from either direction. Once installed, the valve creates a physical barrier that rats cannot push through or chew past, eliminating the drain as an access point without requiring ongoing maintenance or monitoring. The flap sits in a resting closed position and only opens under water pressure from normal drainage use, then returns to closed immediately after flow stops.

Built from heavy-duty stainless steel to withstand constant water exposure, chemical drainage products, and the corrosive environment inside waste systems. The material won't rust, degrade, or weaken over time, and the solid metal construction resists gnawing attempts from rats trapped on the wrong side of the valve. The unit can be removed if needed for maintenance or system changes.

Suitable for residential and commercial properties where rats are entering through drainage systems or where prevention is needed in high-risk areas. Also available in a 6-inch (150mm) diameter for larger drainage pipes.

Key features:
Single-flap one-way valve — allows rats to exit the drainage system but blocks re-entry from either direction, eliminating drains as an access route
Maintains normal drainage function — flap opens under water pressure during use and returns to closed position immediately after flow stops
Heavy-duty stainless steel construction — resists constant water exposure, chemical drain products, and corrosive waste system conditions without rusting or degrading
Long-term protection — provides continuous barrier once installed without ongoing maintenance or monitoring required
Gnaw-resistant solid metal — rats cannot chew through or damage the valve to regain access
Removable if needed — can be taken out for maintenance or system changes

Diameter:
4" / 100mm

Contents:
1 x Drain Rat Blocker Single Flap Valve