A Maß is a full litre, and the Maßkrug that holds one is the most physically demanding glass in beer. Filled, it weighs somewhere near two kilograms. Everything about it is built for that load and for a long session: thick dimpled walls, a heavy base, and a substantial handle.The handle is the functional heart of it. It keeps your hand entirely off the vessel, and the mass of glass acts as a thermal buffer, so a litre of Helles stays drinkable far longer than it has any right to. The dimples add rigidity and grip, and they make the beer glitter under a beer tent’s lights, which does no harm either.Historically these were stoneware rather than glass, often with a hinged pewter lid. The usual explanation is that German sanitary regulations after the Black Death required drinking vessels to be covered against flies. It is repeated everywhere and is plausible; treat it as tradition rather than documented fact. Clear glass took over once glassmaking got cheap enough for people to want to see what they were drinking.Smaller handled mugs exist too: the half-litre Seidel is the everyday German pour, and it is a far more sensible choice for most occasions than a full Maß.Suits: Helles, Märzen and Oktoberfestbier, Dunkles, and any lager you intend to drink a great deal of. Not for anything strong, and not for anything you want to nose.