Split bolt connector (looks like someone taped over a bug) used to mechanically join two or more wires together.
Hey Jim-Bob I need three #6 bugs right quick.
The identifying mark of an Nationally Recognized Testing Laboratory (NRTL). This is placed by the this is placed by the manufacturer before it leaves the factory. Underwriters Laboratories Inc. (UL) is the most common listing mark seen in electrical materials and equipment. The Occupational Safety and Health Administration (OSHA) keeps the official list of NRTLs as well as a list of what type of equipment they are allowed to list, on their website.
"Inspector said all the shower fixtures have to have the UL bug for Damp Locations."