6 inch x 4 inch Strong Back Shielded Reducing Coupling Connects Cast Iron, Copper, PVC, Steel or Lead Pipe

6" x 4" Flexible Transition Coupling – Engineered for Mixed-Material Connections

The 6" x 4" flexible coupling is designed to join dissimilar piping materials in gravity-flow or non-pressurized systems. It facilitates direct transitions between 6-inch and 4-inch pipe sizes, allowing for secure and efficient connections between cast iron, PVC, copper, steel, or lead piping systems.

Manufactured from elastomeric PVC and secured with stainless steel shear bands and clamps, this coupling maintains structural integrity across pipe transitions while accommodating minor misalignments and expansion/contraction. Its robust construction is suited for both new installations and repairs where mixed-material systems are present.

Key Features

• ✅ Multi-Material Compatibility – Designed for use with cast iron (service and no-hub), plastic (Schedule 40 PVC and ABS), steel, copper, and lead pipes.
• ✅ Step-Down Transition – Reduces 6-inch to 4-inch pipe diameters while maintaining leak resistance and system alignment.
• ✅ Elastomeric Flexibility – Neoprene or PVC body allows for vibration absorption and thermal movement.
• ✅ Corrosion-Resistant Components – Equipped with 300-series stainless steel clamps and shear ring to maintain long-term mechanical performance.
• ✅ Code-Compliant – Meets or exceeds ASTM C1173 and CSA B602 requirements for sanitary drainage and DWV connections.

Technical Specifications

• Size: 6" x 4"
• Body Material: Flexible PVC or neoprene (ASTM C564)
• Clamp Material: Stainless steel (ASTM A240 Type 301/304)
• Working Temperature Range: -30°F to 140°F
• Applications: Non-pressure drainage, waste, and vent systems

Installation Guidelines

Installation requires only standard hand tools—no special equipment or solvents. Pipes should be clean, cut square, and properly deburred. Position the coupling evenly over both pipe ends, then torque stainless clamps to manufacturer-specified values (typically 60 in-lbs). Ensure system is aligned and free of tension before final tightening. Do not use in pressurized applications unless explicitly rated for such use.

Typical Use Cases

This coupling is commonly used in DWV systems, utility retrofits, and sanitary sewer laterals where different pipe materials or diameters intersect. Its use is particularly advantageous in remodel or repair work where full pipe replacement is not feasible.

Note

Flexible transition couplings are not intended for use under continuous internal pressure. For pressurized systems, consider shielded couplings rated for pressure retention or mechanical joint fittings.