• Also called a lag bolt.

• Stronger than a wood screw, it is not threaded all the way up to the head and can come in large sizes and lengths.

• Lag screws are a sturdy fastener used to connect heavy lumber and other materials that must bear an intense load.

• Lag screws require a pre-drilled hole to install.

• They are used for wrenching into wood surfaces or inserting into lag shields in masonry.

• They have a hex head and coarse threads.