D 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. D Whirlpool TDLR 6231L FR/N, Top-load, 6 kg, B, 76 dB, 1200 RPM, D Whirlpool TDLR 6231L FR/N. Loading type: Top-load. Rated capacity: 6 kg, Spin-drying class: B, Noise level (spin): 76 dB, Maximum spin speed: 1200 RPM. Product colour: White. Width: 400 mm, Depth: 600 mm, Height: 900 mm. Energy efficiency class: D