The term "grapefruit knife" can refer to a type of knife with short, serrated twin blades about 2mm apart, used to separate the sides of each section from the dividing membrane.[1][2][3] Some grapefruit knives incorporate both types, a double-sided curved blade on one side and the parallel twin blades on the other. Another type includes an angled tip and double sided serrated blade. When both types are used, the result is an intact-looking fruit with sections which lift out easily - especially if a "grapefruit spoon" is used.[4]