A Title 10 Letter states that a retired reservist has completed the required years of service and is eligible for retired pay upon application at age 60.

If veteran is NOT a retired reservist, advise requester:
“The document or information requested is not on file.  A Title 10 Letter is issued to National Guard and Reserve retirees only.”

If veteran is a retired reservist and Title 10 Letter IS in file:
Furnish a photocopy of letter along with any other documents requested. Often the DD Form(s) 214 is also requested.

If veteran is a retired reservist and Title 10 Letter is NOT on file, refer request and record to:

AIR FORCE:	HQ, ARPC ATTN: DSMR 6760 E. Irvington Place Denver, CO  80280
ARMY:	Commander AR-PERSCOM ATTN: PSP-T 1 Reserve Way St. Louis, MO 63132-5200
NAVY:	Naval Reserve Personnel Center 4400 Dauphine Street New Orleans, LA  70149-7800
MARINE CORPS:	MARCOR Reserve Support Command 15303 Andrews Road Kansas City, MO  64147-1207

If veteran retired from the National Guard and Title 10 Letter is NOT on file:
REFER requester to the Adjutant General of the state in which service was performed.

Source:  NPRC 1865.123