The US2 is quite similar to the very popular Bach 7 rim - the difference is in the inner edge of the rim which is a slightly softer contour leading to a smaller cup diameter off a similar high-point, cushioning the lip. Both US2 and B7 should be considered by players of Bach 7 (as also the US2 17.25) as the manufacture of the Bach and other manufactures has varied a little over time. The 18.0mm Cup diameter model is identical to the standard US2 but for the whole profile being moved out to give a wider cup diameter.
Available in 7 finishes.
US2 18 rim
Measured at 1.25mm (0.050") depth