The Helical Coupler is used on the DELTA/DELTAI, A200/A200I, A2000/A2000I Fiber instruments. It couples the agitator shaft with the motor to provide sample agitation within the vessel. 

For the A200/A200I instruments, refer to Service Procedure Packing and Agitator Replacement (FS004) shown below.
For the DELTA and A2000 instruments, refer to Service Procedure Packing and Agitator Replacement (DES002) shown below.