Benchmade 290BK Full Immunity

The Benchmade 290BK Full Immunity is a compact EDC folding knife in the Crater Blue version with a handle in anodised 6061-T6 aluminium. The 63.2 mm Wharncliffe blade is in CPM-M4 with a Cerakote finish, and the knife locks with an AXIS lock. At 65 g and 87.9 mm closed, it disappears in your pocket, yet has a blade built for precise work.

The Full Immunity is Benchmade's take on a small folding knife with a high-performance steel and a full-size lock. The Wharncliffe shape, with a straight edge and the point in line with the edge, makes the knife well suited to cutting packaging, cord and precise cuts where you need to see where the point lands. The 290BK has a Crater Blue handle; the sister model 290BK-1 is the same knife with a Burnt Bronze handle.

CPM-M4, Wharncliffe blade and AXIS lock

Five features that give a lot of knife in a small format:

• CPM-M4 high-speed steel (62–64 HRC): Powder steel from the tooling world with high wear resistance and toughness. It holds its edge longer than most stainless EDC steels and tolerates high hardness without becoming brittle – but it is not stainless and needs more care.
• Cerakote finish: The ceramic coating protects the blade flats against rust and wear, which is particularly relevant on a non-stainless steel such as M4. The edge is uncoated and must be kept dry and oiled.
• 63.2 mm Wharncliffe blade, 2.29 mm thick: The straight edge gives full contact with the cutting surface, and the point is easy to control in precision work. The thin stock gives low cutting resistance.
• 6061-T6 aluminium handle: Anodised aluminium in Crater Blue gives a stiff handle at low weight. The handle is 12.7 mm thick and has a lanyard hole.
• AXIS lock and reversible Mini Deep Carry clip: The crossbar lock works the same from both sides, so the knife is Ambidextrous. The black oxide tip-up clip is reversible and lets the knife ride deep in the pocket.

Maintenance and safety

• Wipe the blade after use and always keep a thin film of knife oil on the edge – M4 is not stainless and can develop rust spots if left wet.
• Give the AXIS lock and pivot a drop of oil regularly, and do not use the knife as a pry bar or screwdriver.
• Keep your fingers away from the edge when folding the blade in, and guide it all the way in with the lock pulled back.
• Check the regulations in your country before carrying the knife in public.