the nitro can is a widgetless can of beer that offers a smooth, foamy head of beer similar to that served in a pub. yardley, pennsylvania based vault brewing have developed this packaging method. &ldquowidgets&rdquo are plastic containers that are either fixed to or float in the can and get &ldquocharged&rdquo so that when customer open the can, the nitrogen is released and cascades in the glass as one pour. this technology is helpful but has three major flaws 1 it&rsquos very expensive and wasteful 2 floating widgets are not easily available 3 the fixed widget idea is flawed as it results in a volcano effect once the can is opened. there are essentially two types of widgets in the market to deliver that draftlike creamy beer head. brewing giant diageo has a patented solution that uses a floating ball widget that is charged with nitrogen during the canning process. can experts ball corporation has a different technological take on it. they use a widget that is fixed to the bottom of a can that&rsquos also charged with nitrogen whilst canning. vault beer sought a different solution by doing away with a widget device entirely and worked out a way to nitrogenate the can midpackaging using a gravityflow filler perfected during a trialanderror process.