BFK N690 BLACK

The Extrema Ratio BFK N690 Black is the full-size folder in the BFK series, designed for pocket carry, everyday work, and dependable handling. For nearly 30 years, Extrema Ratio has produced knives for users who demand uncompromising reliability. The BFK follows the same philosophy with precisely machined scales, tight tolerances, and a solid construction that inspires confidence every time the knife is opened or closed.

Crossbar Lock – secure and ambidextrous

At the heart of the BFK is the Crossbar Lock system, securing the blade with a solid, play-free lockup. The mechanism can be operated with one hand from either side, while keeping the fingers clear of the edge's path when closing.

This allows for fast opening and controlled closing. The robust lock engages with a solid, reassuring sound, and its smooth operation quickly becomes second nature.

Designed for everyday carry

The BFK features a reversible pocket clip, allowing fully ambidextrous carry. The clip keeps the knife discreetly positioned along the edge of the pocket. At just 102 g, the knife remains lightweight and unobtrusive throughout the day while still being readily available whenever needed.

Proven N690 blade steel

The blade is made from Böhler N690 stainless steel hardened to 58 HRC. This proven steel combines hardness, toughness, and reliable long-term performance, making it well suited to a knife designed for everyday use.

The 82 mm blade features a flat grind and measures 2.7 mm thick. The Black version is finished with a MIL-C-13924 burnished coating, giving the blade its distinctive dark, non-reflective appearance.

BFK – five variants, different materials

The BFK series is available in several configurations, each offering a different combination of handle material and blade finish:

• Black: Aluminum handle with burnished blade – simple, functional, and entirely black.
• Tactical Mud: Aluminum handle with burnished blade in a warmer tone.
• Green: Carbon fiber handle with stonewashed blade – lightweight, rigid, and contemporary.
• Avio: G10 handle with stonewashed blade. G10 does not absorb water and remains dimensionally stable despite temperature changes.
• Tobacco: Micarta handle with stonewashed blade. The material develops greater character and depth through use over time.

Product Features

• Full-size folding knife for EDC and everyday work
• Böhler N690 blade steel, 58 HRC
• 82 mm blade length
• 195.5 mm overall length
• 2.7 mm blade thickness
• Flat grind
• Black MIL-C-13924 burnished finish
• Crossbar Lock
• One-handed operation
• Ambidextrous lock operation
• Reversible pocket clip for fully ambidextrous carry
• Precisely machined handle scales
• Anodized Anticorodal aluminum handle
• Weight: 102 g
• Designed and manufactured by Extrema Ratio