C means that the product is rated in its category in terms of energy efficiency. The Energy Labeling system is based on EU Regulation 2017/1369/EU. C Bosch Serie 6 WAU28U90, Front-load, 19.8 lbs (9 kg), B, 71 dB, 1400 RPM, C Bosch Serie 6 WAU28U90. Loading type: Front-load. Drum capacity: 19.8 lbs (9 kg), Spin-drying class: B, Noise level (spin): 71 dB, Noise level (wash): 47 dB, Maximum spin speed: 1400 RPM. Product color: White. Width: 23.5" (598 mm), Depth: 23.2" (590 mm), Height: 33.3" (845 mm). Energy efficiency class: C