Spyderco Police 4 Lightweight Folding Knife 4.38" K390 Satin Plain Blade Blue FRN Handles
easoned Spyderco enthusiasts know that Spyderco model numbers are sequential to the chronological development of the knives they represent. With very rare exceptions, like the C06 Tusk, the lower a model's number, the longer it's been around.
Based on that rule, a quick scan of the current Spyderco catalog will reveal that the C07 Police Model is the oldest Spyderco design currently still in production. The secret to its longevity is not only its iconic status as one of the preeminent tactical folders of all time, but also its ability to adapt, evolve, and constantly earn new followers. The latter quality is clearly evident in the latest version of this venerable design: the Police 4 Lightweight K390.
EVOLUTION OF THE POLICE MODEL
When Spyderco literally defined the form of the modern folding knife back in 1981, some of the very first end users to embrace their unorthodox designs were law enforcement officers. They immediately recognized the advantages of clip carry, swift one-handed opening, and a voracious serrated cutting edge and quickly became some of their most devoted customers. As their early models became the "go-to" cutting tools of savvy officers, they also began asking for a purpose-designed Spyderco folder optimized for their needs. Specifically, they wanted a slim, easy-to-carry knife that also offered a hand-filling grip and a substantial blade that could work as both a utility tool and a potent back-up defensive weapon in an officer-survival situation.
In 1984, Spyderco responded to that calling with the original Police Model. Designed by company founder Sal Glesser, the Police was crafted entirely from stainless steel. Its long, hollow-ground blade had a prominent swedge (unsharpened back bevel) to ensure an acute point and was paired with a smooth, square-edged stainless steel handle, a stout lockback mechanism, and a clip configured for right-side tip-down carry. For left handers and officers who wanted the knife as a handgun-retention tool, dedicated left-handed versions were also produced.
In the early 1990s, the Police Model's design was refined to include chamfered handle edges and a revised lockback. The second-generation version also inspired a number of different variations, including knives with aluminum, titanium, G10, and carbon fiber scales, various blade steels, and even all-black versions. Years later, the handle was also updated to accept a versatile, four-position clip, that provides a choice of tip-up or tip-down carry on either side of the body.
While the "old-school" Police Model continued its reign, in 2008, it was joined by the Police 3, which was very similar in design, but boasted a number of key differences. It featured full stainless steel liners, high-traction textured G10 scales, a four-position pocket clip, and a broad, full-flat-ground VG10 stainless steel blade with an index-finger choil. That knife also earned a devoted audience—and some strong customer feedback that ultimately led to the even more refined Police 4, which Sal Glesser admittedly tuned to meet the needs of a broader audience than law enforcement officers alone. According to Sal, "I designed the Police 4 to include what I would like in a knife, more than what a LEO might like. It's still a kissing cousin, and large for most people. I widened the blade, enlarged the hole and selected a steel that I like to use."
Although very similar in overall spirit and construction to its predecessor, the Police 4 incorporates a number of subtle, but significant, ergonomic refinements. Perhaps more importantly, it marked the transition from a stainless steel blade—a longstanding Police Model tradition—to a tool steel blade crafted from Böhler-Uddeholm K390. Renowned for offering an exceptional combination of edge retention and toughness, K390 is ideally suited to the challenges to which Police 4 users typically put its long, broad, full-flat-ground blade.
Throughout its evolution, the Police had always been constructed from solid materials that offered serious heft to match its hand-filling size. While that certainly appealed to many end users, others preferred the lighter weight and enhanced grip texture of Spyderco's lightweight models. In 2019, they bridged the gap between these two schools of thought by creating the Police 4 Lightweight.
Its design profile is identical to the G10-handled Police 4, but its handle is constructed in the style of our tried-and-true lightweight models, featuring skeletonized stainless steel liners, injection-molded fiberglass-reinforced-nylon (FRN) scales, high-traction Bi-Directional Texturing, and a full-flat-ground VG10 stainless steel blade.
THE BEST OF ALL WORLDS
While "perfect" is an elusive concept, after developing the Police 4 Lightweight, Spyderco realized there was one popular element of the G10-handled version that hadn't been incorporated—the K390 tool steel blade. Since they were already hard at work introducing K390 versions of their other lightweight models, it made perfect sense to follow suit with the venerable Police Model as well. The result is, in many ways, the best of all worlds.
The Police 4 Lightweight K390 starts with the highly refined ergonomics and completely ambidextrous functionality of the Police 4 profile, which reflect decades of user feedback and careful fine tuning. It adds all the advantages of their time-tested lightweight handle construction, as perfected through the long evolution of the fourth-generation Endura 4 and Delica 4. Finally, it supercharges the knife's cutting performance, edge retention, and strength with the use of K390 blade steel. The powerful synergy of all these elements yields one of the most capable folding knives they've ever created. And, like all members of our growing K390 family, the Police 4 Lightweight features the distinctive blue handle color of this elite breed—all too appropriate given the long, proud history of service of this distinguished design.
Like most blade steels, the best way to understand the "magic" of K390 is to start with the reason it was developed in the first place. According to its creator, BÖHLER, K390 MICROCLEAN was developed to "meet the demanding wear resistance and compressive strength requirements of cutting, blanking and punching applications, for cold forming applications, and for parts which are subjected to abrasive wear in plastics processing." In simpler terms, K390 was created specifically to excel at some of the most demanding industrial processes imaginable.
K390's remarkable qualities include good machinability, excellent grindability, uniform low dimensional change during heat treatment, excellent tolerance for long soak times during heat treating, and optimal EDM (electrically discharged machining) characteristics. The key to achieving these properties is BÖHLER's advanced powder-metallurgy production process, which prevents alloy segregation and ensures a uniform chemical composition, uniform carbide distribution, and small carbide size.
As impressive as all this sounds, when it comes to appreciating K390's potential as a blade steel, it helps to have other established steels as a basis for comparison. It helps even more when a steel-savvy custom knifemaker and popular Spyderco collaborator "cracks the code" for you.
- Blade Length: 4.38" (111 mm)
- Cutting Edge: 3.97" (101 mm)
- Closed Length: 5.64" (143 mm)
- Overall Length: 9.97" (253 mm)
- Blade Material: Bohler K390 Tool Steel
- Blade Thickness: 0.118" (3.0 mm)
- Blade Style: Drop Point
- Blade Grind: Full Flat
- Blade Finish: Satin
- Handle Material: Blue FRN
- Liner Material: Stainless Steel
- Locking Mechanism: Lockback
- Pocket Clip: Black Stainless Steel (Tip-Up/Down, Right/Left Carry)
- Weight: 4.2 oz. (119 g)
- Made in Japan