BJCP 5B
A dark, strong, malty lager beer.
Decoction mashing and long boiling plays an important part of flavor development, as it enhances the caramel and melanoidin flavor aspects of the malt. Any fruitiness is due to Munich and other specialty malts, not yeast-derived esters developed during fermentation.
Einbecker Ur-Bock Dunkel, Pennsylvania Brewing St. Nick Bock, Aass Bock, Great Lakes Rockefeller Bock, Stegmaier Brewhouse Bock
You can view the complete style details on the BJCP website. The 2008 style guide is obsolete but there is a similar 2015 style that you can view below...
OG: 1.064-1.072
FG: 1.013-1.019
IBU: 20-27
SRM: 14.0-22.0
ABV: 6.3-7.2%