This is a Civil War Model 1858 smooth side canteen.  Marked Co. H, 5th Rack, No. 15.  There is some other printing, I can only read Quartermaster etc.  This canteen is pictured in Ordnance Memo 29.  (See copy enclosed).  The triangle loops have been remodeled in the period.

NOTE:  The leather strap hanger is a reproduction - not original.