USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Drawing of the McKenzie Valve & Machining LLC UNNR Design Threaded-by-Threaded Full Port Ball Valve

Document Series
Reference Materials
Kurt Eichenlaub
Subject Hazardous Materials
McKenzie Valve, RWD, Railworthiness Directive, UNNR

DOT is committed to ensuring that information is available in appropriate alternative formats to meet the requirements of persons who have a disability. If you require an alternative version of files provided on this page, please contact
Last updated: Wednesday, March 25, 2015