Unprotected, flat top.
This is a great cell for Maglite Mods, or in other places where you want to replace "C" sized cells with a lithium cell for driver/LED upgrades. This cell is about the same length as a standard "C" cell, and is also slightly narrower than most 26650s so that it can fit into most "C" sized tubes (see below), which are often too short for a 26650 cell.
Please note that these will not fit all "C" cell tubes. Some Maglites/other "C" cell tubes are smaller diameter than others.