The SOG Seal Pup M37. 

SOG makes some really good gear, and the SOG Seal Pup is no exception. Selling around the $60-$80 range, you get a lot of knife for the money.

The seal pup is a lighter more compact version of the the SOG Seal Knife 2000 or Model S37.  The SOG Seal Knife was selected as the highest ranked knife among the Navy Seals.  

The rubber feel of the handle is very comfortable, an important and sometimes overlooked quality in a knife.  The blade is AUS-6 stainless, with a powdercoated finish.  The finish can tend to wear off a little after repeated use, but that is generally just a cosmetic issue.

The blade length is 4.75 inches, and the overall length of the knife is 9 inches.  Weighing in at just 5 oz., the SOG seal pup is one of the lighter fixed blade knives available.  It is popular with scuba divers, and just requires a rinse after being in saltwater, just as you would do with any salt water equipment.  The nylon sheath has some steel grommets in it which will rust with prolonged saltwater exposure though, dont understand that one.  There is also an optional Kydex (tm) sheath with a groove to expose the blade as a strap cutter - nice feature but not all that practical if you have it strapped to your leg.