Earlier Vietnam era dive knife.  These seem to be much harder to find that the model 14s and 15s.  This knife has the very desirable “separate S” logo and unlined thong hole, along with the earlier greenish black micarta handle. Comes with the original waxed rough back dive sheath.  This knife is in mint condition. Appears to have been stored in the sheath and never used. Sheath shows some marks/discoloration from storage and banging against stuff.