Traditionally, knife makers have always had to compromise between the two types of steel

• High Carbon steels - hard and keeps its edge well, but rusts easily
• High Chromium steels - shiny and non-rusting, but too soft to hold an edge.

 Then came the H1 steel, which broke all the rules.

Developed by a Japanese steel foundry, H1 is a precipitation hardened steel that has .1% nitrogen (acts like carbon in the steel matrix without rusting like carbon does). H1 holds a sharpened cutting edge equivalent to many premium carbon steels but without developing rust or pitting.
 
So if you're someone who regularly uses knives around water, you should definitely be checking out Spyderco's range of salt knives.  Along with being RUST FREE, the knives also have an enlarged Spyderco blade hole to help with one handed opening, even with gloved or wet hands. They have lightweight fiber reinforced nylon handles with checkerboard texturing, Boye dent lock backs, and side to side reversible pocket clips mounted at the butt end. There is a lanyard hole for backup cord attachment when working in and around water.