HP Take-Up Reel Q6706A is compatible in the following HP Models:

HP DesignJet Z6100 Printer series

HP DESIGNJET Z6100 42-IN PRINTER - Q6651A
HP DESIGNJET Z6100PS 42-IN PRINTER - Q6653A

HP DesignJet Spindles

HP DESIGNJET Z6100 42-INCH TAKE-UP REEL - Q6706A