The API 682 standard provides for different applications of the mechanical seal that can be selected according to operating conditions; these can be divided into 3 categories (1, 2, 3); 3 types (A,B,C); 3 configurations (1,2,3). The configurations can in turn have 3 different designs: seals installed in tandem (face to back), Seals installed back to back, seals installed face to face.