The pipe has a 4-inch cap with a square nut in the middle.
From the dailyherald.com
They are usually made of low grade steel, have a slot or Phillips drive, and are used to join sheet metal parts using a hex or square nut.
From the en.wikipedia.org
Shih and his colleagues reported in the Nature paper that they were able to construct a number of DNA objects, including a genie bottle, two kinds of crosses, a square nut, and a railed bridge.
From the sciencedaily.com
They also gave us a treat of chocolate nut covered square pieces of toffee.
From the gothamgal.com
Put a half-teaspoon nut filling in center of each square.
From the stltoday.com
A chief knows when to count every nut, bolt and screw and where to use square footage from history.
From the jobview.monster.com
The 800-square-foot kitchen and warehouse is bright and neat and filled with jars of nut butters and containers of dried fruits, as well as food scales and mixers.