In archery, the ferrule is the connecting tube between the shaft and the tip on the arrow. Generally, it is made of alluminum or plastic, and in reusable arrows it is commonly threaded since the tip or shaft often needs to be replaced.

                              ::                                  
                        :==-*@:                                   
                  -++++=  :-                                      
            =++++=      --                                        
      =----:         *+:..:---------------------------------------
    *                         |   Ferrule  |
      =----=.         .*#.::--------------------------------------
            .=+++++.     ::                                       
                   .++++=- .-                                     
                          .=-*@#