The WMF Bistro 1-Step Series is a line of ultra-automatic (1 step) commercial espresso machines that are built for high volume applications of up to 300 espressos per hour. All WMF Bistro models are plumbed (connected to a water line), and feature 2 coffee hoppers.
The WMF Bistro 1-Step machines (ultra-automatics) all have milk inputs. The WMF Bistro machines automatically draw milk from an external source, and froth it or steam it to order. One of the WMF Bistros has two milk inputs so that you can select from either of two milk sources (e.g., whole, skim, soy, etc.).
And the WMF Bistro 1-Step machines can be ordered with the "Milk Power" option, which is a high volume external automatic frothing wand that allows you to keep up with very high volume cappuccino and latte orders, since it allows the operator to do very high volume frothing while leaving the basic espresso operations to the machine. Note that the "Milk Power" option on the WMF Bistro requires more electrical power than the basic model.