The designer Johan Jonker and Pettie Petzer engineer developed the Hippo Water Roller, a roller that facilitates the transport of water in rural areas. To design this can which also act as a wheel, the two South Africans used the rotational molding technique. The Hippo Water Roller holds up to 90 liters of water and you feel 10Kg maximum moving it. This rolling tank allows rural people to carry up to 5 times more water with greatly reduced effort.