[size=large]if just another name for a bottle cap. I know many used to call the bottle cap a "pop top" because that's what they were, the TOP of the bottle of pop.
"Pull Tabs,} as we know them, have now been around for about 40 years and include a wide-ranging assortment of the old ring-pull w/beaver tail types, as well as the more modern "pry-tab" design. The rectangular tabs that were intended to stay on the can after prying the metal back to create a drinking hole.
This about how terms have confused many people, including some dealers and manufactures who don't really detect much. When we got discrimination in the early 70's some models only knocked out bottle caps and foil. It took a short while for discrimination to extend enough to reject the then-newish pull-tabs. Most parks and schools and picnic areas only had the old pry-off bottle caps (also called "Crown Caps" and "Pop Tops") and lesser conductive trash.
Those of us who ventured into 'spooky' areas, such as down by the railroad depot/tracks, or buss depot area, or back behind some of the old business areas, could run into Screw Caps. Those high-conductive trash items were mainly associated with wine bottles and were found where bums, transients, and wine-os hung out. In time, discrimination was increased to include those higher-conductive targets and I can't tell you how many times I read people having problems with them because they expected them to be rejected like other bottle caps. Sure, they ARE bottle caps, but when they started showing up on more popular beverages and in more frequently hunted sites, many newcomers often were confused when the term "Bottle Cap" was used because, while they were caps off of bottle, they are not the type of "Bottle Cap" we refer to in the metal detecting hobby. BC's are the crimped-edge, crown-cap, pop-top type items. SC's are the higher-conductive, aluminum caps that are taller.
Just my opinions and terms of use from over 43 years of detecting.
Monte [/size]