The Spyderco Delica 4 C11FPK390 is the extreme edge retention Delica 4 — Böhler K390 tool steel in a 2.87-inch full flat ground plain edge blade, Blue FRN handle, and back lock, delivering edge retention that substantially exceeds VG-10 and most PM stainless steels in the Delica 4's compact carry platform, in the same Blue FRN colorway as the VG-10 C11FPBL at $40 more — the right Delica 4 for buyers who want the absolute edge retention ceiling in the compact back lock Spyderco platform and are prepared to manage K390's non-stainless corrosion care requirements.

The K390 blade is Böhler's high-performance tool steel — a non-stainless, high-carbon, high-vanadium powder metallurgy steel that delivers extreme edge retention and toughness at the cost of requiring more corrosion care than stainless alternatives. K390 achieves edge retention that substantially outperforms VG-10, CPM-S30V, and most PM stainless steels, placing it among the highest-performing non-stainless steels available in production folders — Spyderco's use of K390 in the Delica 4 platform delivers a compact EDC that holds its edge through cutting sessions that would require resharpening on any VG-10 or conventional stainless variant. The tradeoff for K390's extreme edge retention is a non-stainless steel that requires more attentive corrosion care than VG-10 — K390 will patina and eventually rust if exposed to prolonged moisture, acidic foods, or saltwater without cleaning and light oiling after exposure. For buyers who understand and accept this care requirement, K390's edge retention advantage over VG-10 is the most meaningful steel performance upgrade available in the compact Delica 4 platform without moving to the PM stainless ceiling of CPM S90V. K390 sharpens on conventional diamond stones and ceramic abrasives — its high-vanadium content is more demanding than VG-10 but less extreme than CPM S90V, making it maintainable at home with diamond equipment rather than requiring factory service. The full flat grind maximizes K390's cutting geometry by thinning behind the edge across the full blade width — the same geometry that makes every Delica 4 one of the most efficient slicing compact EDC folders at its price point, here applied to a steel that holds the resulting edge geometry longer. Blue FRN on the K390 Delica 4 creates the same visual carry identity as the VG-10 Blue C11FPBL — Spyderco's signature compact EDC colorway — while the K390 blade delivers a meaningfully different performance ceiling.

• Blade: K390 Böhler tool steel, drop point profile, satin finish, plain edge, full flat grind — non-stainless high-carbon high-vanadium PM tool steel with extreme edge retention substantially exceeding VG-10 and most PM stainless steels; full flat grind maximizes cutting efficiency; requires diamond stones for sharpening; requires cleaning and light oiling after moisture or acidic food exposure
• Handle: Blue FRN (fiberglass-reinforced nylon), textured bidirectional grip, compact Delica 4 profile — chemically inert and lightweight; Blue is Spyderco's signature compact EDC colorway; same visual carry identity as the VG-10 Blue C11FPBL
• Deployment / Lock: Back Lock via Spyderco Round Hole — back lock provides reliable blade security; ambidextrous Round Hole allows one-hand opening from any grip position
• Carry: Approximately 2.50 oz, tip-up right-hand wire clip, compact Delica 4 profile — K390 extreme edge retention at $140; $40 more than the VG-10 Blue C11FPBL for the edge retention premium

Ideal For

Performance-focused EDC buyers who want the maximum edge retention available in the compact Delica 4 back lock platform and are prepared to manage K390's non-stainless corrosion care requirements — the C11FPK390 at $140 delivers K390's extreme edge retention that substantially exceeds VG-10 in the same Blue FRN Delica 4 package at $40 more, suited to buyers who sharpen their own knives, already own diamond stones, and want a compact EDC that holds its working edge significantly longer between sharpening sessions. Buyers choosing between the K390 C11FPK390 and the VG-10 Blue C11FPBL at $40 less who want extreme edge retention over stainless corrosion care simplicity — K390's edge retention advantage over VG-10 is substantial and practically meaningful in daily carry; the tradeoff is non-stainless care requirements that VG-10 does not demand. Knife enthusiasts and steel performance buyers who want to carry K390 in a compact production platform — K390's reputation in the knife community for extreme edge retention at a relatively accessible production price point makes the C11FPK390 the right Delica 4 for buyers who follow steel performance closely and want K390's ceiling in Spyderco's most refined compact back lock folder.

K390 Böhler tool steel that delivers extreme edge retention substantially exceeding VG-10 and most PM stainless steels in the Delica 4's compact carry platform, a full flat grind that maximizes K390's cutting geometry by thinning behind the edge across the full blade, Blue FRN in Spyderco's signature compact EDC colorway, and the back lock in Japan's most refined compact production folder — the Spyderco Delica 4 C11FPK390 is the extreme edge retention compact EDC at $140. Add the Spyderco Delica 4 C11FPK390 to your cart today and get same-or-next-business-day shipping from Columbia, Louisiana, backed by Spyderco's lifetime guarantee. Questions? Call 888-225-9775 — we carry these knives daily.