The Cherne 8"-12" Big-Mouth Plug with 4" Bypass (part #374-088) is a pneumatic bypass plug with an oversized 4" opening for maximum flow-through during sewer testing on 8" to 12" pipe. The Big-Mouth design provides more bypass capacity than standard Muni-Ball plugs — critical when flow volumes are too high for smaller bypass fittings.

Key Features

• 4" bypass — controlled flow-through during testing
• Pneumatic inflation — natural rubber seals round and out-of-round pipe

Technical Specifications

Applications

Municipal sewer air pressure testing, storm drain isolation, large-diameter pipe testing during construction and repair, and compliance testing on trunk mains. Always follow Cherne inflation and back-pressure guidelines.

Questions on sizing or bulk pricing? Call (866) 514-3684 or email us — same-day shipping on in-stock items, tax-exempt purchasing for qualified accounts.