within   commuting   distance,   conflicting employment,   and   other   factors   prevent   some reservists  from  participating  in  the  Selected Reserve. Therefore, reservists affected by any of these  factors  are  assigned  to  the  IRR. While assigned to the IRR, members can still participate in the Naval Reserve training program. Correspondence   courses   are   available   to   both officer  and  enlisted  personnel.  These  reservists also   remain   within   the   Navy’s   mobilization potential.  Additionally,  within  the  limitation  of funds,  personnel  in  the  IRR  who  have  maintained an Active status may participate in 12 to 14 days of  active-duty  training  annually. STANDBY  RESERVE The Standby Reserve consists of reservists who have  transferred  from  the  Ready  Reserve  after fulfilling  certain  requirements  established  by  law. Ready  and  Standby  status  differ  mainly  in  the degree  of  liability  for  recall  to  active  duty. Standby reservists can be ordered to active duty without their consent only in the event of war or an   emergency   declared   by   Congress   or   when otherwise  authorized  by  law.  The  Navy  cannot recall   a   Standby   reservist   to   active   duty   in- voluntarily  until  the  Director  of  the  Selective Service has determined the person’s availability for  duty. The  Standby  Reserve  includes  the  Standby Reserve-Active  and  the  Standby  Reserve-In- active. Standby Reserve-Active The   Standby   Reserve-Active   consists   of reservists  who  have  completed  their  active-duty or Selected Reserve service obligation. They have requested transfer to the Active status list of the Standby Reserve. Officers with at least 18 but less than 20 years’ satisfactory federal service toward retired  pay  for  nonregular  service  can  also  request transfer  to  the  Standby  Reserve-Active.  Addi- tionally,  key  federal  employees  and  personnel expecting  to  return  to  the  Ready  Reserve  but facing  temporary  personal  hardships  may  request assignment  to  the  Standby  Reserve-Active. Standby  Reserve-Inactive The Standby Reserve-Inactive (also called the Inactive  Status  List  or  ISL)  includes  three  groups of  reservists  who  have  been  screened  from  the Ready  Reserve.  The  first  consists  of  those  who did not maintain a satisfactory level of participa- tion.  The  second  consists  of  those  who  allowed their Ready Reserve agreement to expire while in this status. The third consists of those who fit into both  the  first  and  second  group.  While  in  this Inactive status, a member may not participate in training programs, earn retirement points, or be considered for promotion. Reservists transferred to  the  Standby  Reserve-Inactive  may  apply  for reinstatement in the Ready Reserve at any time within the following 3 years. Those members not voluntarily returning to a Ready Reserve status at the end of 3 years are discharged or transferred to  a  retired  status,  as  appropriate. Members on the Inactive Status List may be called  to  active  duty  under  the  same  conditions as   other   members   of   the   Standby   Reserve. However,  a  determination  must  first  be  made  that adequate  numbers  of  qualified  personnel  in  an Active  status  (Ready  and  Standby  Reserve-Active) are  not  available. RETIRED RESERVE The   Retired   Reserve-Inactive   (USNR-RET) consists of reservists who are drawing retired pay or are qualified for retired pay upon reaching age 60. It also includes those who are not eligible for retired pay at any time but desire service or other requirements  for  voluntary  assignment  to  the Retired Reserve in recognition of their contribu- tion to their country and the United States Navy. Their liability for Active service is the same as that for  the  Standby  Reserve. UNIT  CLASSIFICATIONS Selected Reserve units are grouped into three basic  categories,  each  with  its  own  mission  and mobilization  element.  These  primary  categories are  supplemented  by  other  Selected  Reserve  units and  individuals  of  the  Ready  Reserve. In some instances units of the three primary categories   are   unable   to   fill   all   authorized mobilization billets because of a lack of required skills  within  their  particular  geographic  locations. Additional units are organized in these areas when the  necessary  skills  are  available.  These  additional units  provide  a  source  of  Selected  reservists  for immediate   mobilization   to   increase   the   three primary categories. Upon mobilization, they join with Selected Reserve units from other locations at  the  appropriate  mobilization  site. In  addition  to  the  units  of  the  Selected Reserve, volunteer units provide meaningful and 15-3