The Cherne 8" Single-Size Underground Test-Ball (part #041-386) is a pneumatic blocking plug for sanitary and storm sewer testing. Natural rubber inflates to block flow in 8" pipe (usage range 7.00"–8.25" ID). Rated for 17 PSI / 40 ft. head pressure at 25 PSI inflation. The 3.9 lb plug features a 1/4" inflation thread for quick-disconnect fittings and a 3/8" eyebolt for poly-lift line attachment. Designed for underground sewer air tests and back-plug applications.

Key Features

Pneumatic inflation — natural rubber expands to seal round and out-of-round pipe
17 PSI / 40 ft. head pressure — rated for sewer air pressure testing
Full blockage — complete shutoff for sewer air tests and isolation
3/8" eyebolt — attach poly-lift line for manhole deployment and retrieval
Natural rubber — durable construction for underground sewer environments

Technical Specifications

Cherne Part Number	041-386
Pipe Size Range	8"
Usage Range (Pipe ID)	7.00–8.25"
Bypass	None (full blockage)
Max Back Pressure	17 PSI / 40 ft.
Inflation Pressure	25 PSI
Body Material	Natural rubber
Inflation Fitting	1/4" thread (quick-disconnect compatible)
Deflated Length	10.25"
Deflated Diameter	6.75"
Weight	3.9 lbs
Operating Temperature	0°F to 125°F
Pipe Compatibility	All underground sewer and storm pipe types

Applications

Municipal sewer air pressure testing, storm drain isolation, underground pipe blocking for repairs, and back-plug applications. Deploy through manholes using the eyebolt and poly-lift line. Always follow Cherne inflation 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.

Cherne® 8 in. Enchufe de bola de prueba subterránea de tamaño único