QT20R are interchangeable with John Crane type 10R, 10T, 20 and 20R. 

TS10R and TS20R have inserted rotary face (carbon, silicon carbide) and the rotary face can be changed; 
QT20 have integral rotary face GFT and the rotary face cannot be changed. 

QTWB2 is equivalent to John Crane type WB2 teflon bellow seal. 

Type 659 is equivalent to Sealol type 659 and it is Outside Mounted Reverse Balance Teflon Bellow. 
Applications:

For water, oil, acids, alkalis, organic solvents, a small amount of suspended particles and crystallization medium, mainly used in chemical, pharmaceutical, pesticide, water treatment and other industries pump, fluorine plastic pump is the most widely used.