Odyssey's take on the American loose ball bottom bracket, made for use with most 1 piece cranks. It runs the usual cups, cones and loose balls, the layout the USA bottom bracket has always used.

The Dynatron shields are the difference: they sit over the bearings and cones and keep water and dirt out of the races. Bearing cups measure 51mm across the outside and the set suits 7/8" 24TPI crank spindles.