A Miele W1 washing machine with TwinDos automatically doses the correct amount of detergent and fabric softener. This way, you'll never use too much and your laundry will stay as new for longer. You can use the TwinDos system with the included Miele UltraPhase 1 and UltraPhase 2 detergent, but you can also use your favorite detergent or fabric softener. You'll need TwinDos refill reservoirs. Because you use the exact right amount of detergent, you'll need to rinse less. As a result, a Miele TwinDos washing machine uses less water and energy.