productive  training.  These  units  train  qualified Ready reservists who are required for full mobili- zation but who are not members of the Selected Reserve. These personnel remain affiliated with the Naval Reserve in an Active capacity and are available  for  recall  under  public  law.  Volunteer units train in a nonpay status and serve as a skill resource from which billets in the Selected Reserve can  be  filled. Category I Category I units are those with organic equip- ment.  Each  is  a  self-contained  unit  designed  to provide complete capabilities upon recall; that is, a ship, squadron, or battalion. Selected reservists fill all manpower requirements but may be com- bined, as in many instances, with an active-duty nucleus. Each unit has its own hardware, which it  “owns  and  lives  with,”  or  will  use  predesignated hardware upon recall. Hardware required varies from  weapons  systems,  ships,  and  aircraft  to equipment   and   tools   necessary   for   mission performance. Category II Category  II  units  are  augmentee  units  for Active Navy ships, squadrons, and mobile units. They are mission-oriented, task-performing aug- mentation  units  with  a  mix  of  specific  skills.  Each unit has specific skills needed to bring an active- duty Navy operating platform (a ship or aircraft squadron) up to organizational (battle) manning or  full  complement.  A  Category  II  unit,  tailored to a specific ship class or aircraft squadron type, operates  equipment  and  uses  facilities  of  the parent unit. Category III Category  III  units  are  augmentee  units  for  the Shore   Establishment.   These   units,   similar   in character to Category II, represent the mobiliza- tion billets needed to meet Shore Establishment organizational  manning  requirements.  Category III activities are geographically fixed rather than mobile  units.  Each  is  tailored  to  strengthen  a specific  type  of  nonplatform  activity,  such  as  a shipyard, air station, or staff, Category III units normally  operate  the  equipment  and  use  the facilities   of   the   mobilization   activity.   The requirements   of   this   category   are   as   equally important in the accomplishment of the wartime mission  as  are  the  combat  requirements. RESERVE  TRAINING The  Selected  Reserve  receives  ongoing  training throughout  the  year.  The  nature  of  the  training depends  on  each  reservist’s  individual  designator/ rating and job skill. It also depends on the type of  unit  to  which  the  member  is  attached.  Training takes   place   during   unit   drills   and   while   the reservist  is  performing  active  duty  for  annual training  (AT).  A  drill  is  a  period  of  training authorized for inactive-duty reservists, in either a  pay  or  nonpay  status. Members  of  the  Selected  Reserve  normally perform 48 drills each year. Each “drill” consists of  a  4-hour  period.  For  most  units,  regularly scheduled drills are conducted one weekend per month.   This   multiple   drill   permits   a   greater concentration  of  effort  and  extended  involvement. In  some  instances,  drilling  only  one  evening  a week  better  serves  the  unit’s  mission  or configuration. Certain units are scheduled for inactive-duty travel  training  (IDTT).  During  IDTT,  members receive training at fleet training sites or aboard ship. Selected  individuals  and  units  may  perform additional paid drills to maintain peak efficiency or  to  complete  their  assigned  mission,  or  both. For example, flight crews and certain critical units often  require  additional  drills.  The  number  of regularly scheduled or additional paid drills may vary  with  need  and  the  availability  of  funds. Although   not   members   of   the   Selected Reserve,  Ready  reservists  in  the  IRR  category  and members   of   the   Standby   Reserve-Active   may volunteer  to  participate  in  regularly  scheduled drills. Although such members are ineligible for drill  pay,  they  may  earn  retirement  points  by taking an active part in these drills. ACTIVE  DUTY  FOR  ANNUAL TRAINING  (AT) The  careful  coordination  of  AT  with  drilling sessions  provides  members  of  the  Selected  Reserve with   practical   experience   that   clarifies   or supplements   other   instruction.   On   some occasions,  reservists  may  train  on  Active  Fleet ships for a weekend, or, in some cases for 2 weeks or  more.  Reservists  may  receive  this  shipboard training as an entire unit, as a team from a unit, or  on  an  individual  basis. All  members  of  the  Selected  Reserve  must receive  a  minimum  of  12  to  14  days  of  annual training.  Members  of  the  IRR  may  be  assigned 15-4