The three black dots are silicate gaskets, which stabilize the temperature.Slight color difference should be acceptable due to the light and different screen.Material: glassStyle: Nordic styleColor classification: black, white, green, red, coffee colorPopular elements: small and freshLarge-capacity double-layer insulation pot.24h long-lasting heat preservation, one pot of drinking water for one family.1*Insulation potThere may be 1-2cm difference according to manual measurement.We provide best product and service, if you have any problem, please let us know, we will solve the problem