bag plug

bag plug

[′bag ‚pləg]
(engineering)
An inflatable drain stopper, located at the lowest point of a piping system, that acts to seal a pipe when inflated.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

bag plug

An inflatable drain stopper; when inflated, it acts to seal a pipe; usually located at the lowest point of the piping system
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.