Trivisa Firefly Ultra-S YD04-S-M M390 Blade Titanium Handle Crossbar Lock Folding Knife

Designed by the TRIVISA team, the Firefly Ultra-S YD04-S-M pairs a compact profile with premium materials for everyday carry and outdoor use. Its 2.99-inch M390 stainless steel blade features a bead-blasted finish and a swedge design. Known for strong wear and corrosion resistance, M390 helps the edge stay sharp through regular tasks, though its hardness may require diamond abrasives for sharpening. A titanium handle keeps the knife lightweight, while the crossbar lock provides secure operation. Ceramic ball bearings support smooth opening. Measuring 6.69 inches overall and 3.7 inches when closed, this folding knife weighs just 3.07 ounces. With a 76 mm blade and 87 g weight, it is a practical companion for hiking, camping, fishing, hunting, and everyday carry.

M390 Blade Introduction

M390 is an advanced powder-metallurgical stainless steel utilizing high chromium and vanadium content to deliver exceptional wear resistance and industry-leading corrosion resilience. It excels at retaining a razor-sharp edge under prolonged use; however, this extreme hardness renders the blade notably difficult to sharpen or reprofile without diamond abrasives. Additionally, its fine microstructure, while offering superior edge stability, sacrifices some structural toughness and may be more prone to chipping under heavy lateral stress.

Specification

Designer:TRIVISA Team
Style:Swedge
Blade Material: M390 Steel Blade
Blade Finished: Bead Blast Finished
Handle Material:Titanium Handle
Lock Style:Crossbar Lock
Hardness:60±2HRC
Bearing:Ceramic Ball Bearing

Size:
Overall length-6.69"(171mm)
Blade length-2.99"(76mm)
Closed length-3.7"(95mm)
Blade width-0.9''(23mm)
Blade thickness-0.13''(3mm)
Net Weight:3.07oz(87g)

Usage:Outdoor survival,EDC,hunting,fishing, hiking and camping

Trivisa Firefly Ultra-S - Bead Blast M390 Swedge Blade in a Fluted Titanium Frame

The M390 swedge blade on the Trivisa Firefly Ultra-S is finished in bead blasted, riding on a silver fluted titanium handle with a crossbar lock and ceramic bearings at 87 g (3.07 oz). More folding knives and EDC gear at EDCMALL.

M390 Behind a Fluted Titanium Frame Built for Daily Carry

The Firefly Ultra puts Bohler M390 - the powder-metallurgy benchmark with roughly 20 percent chromium and a dense vanadium carbide field - behind a 2.99 inch swedge blade on 3.0 mm stock, hardened to 60+/-2 HRC. That is a month of packaging and cord duty between touch-ups, with corrosion resistance that laughs at sweaty pockets and wet weather. The fluted titanium scales are machined with a groove-and-rivet relief that indexes your fingers and cuts glare, and the crossbar lock plus ceramic bearing pivot keep the action crisp at 87 g (3.07 oz). Compare M390 with CPM-S35VN, CPM-20CV and CPM-MagnaCut in the table below.

Why the Trivisa Firefly Ultra Belongs in Your Pocket

• 2.99 inch Bohler M390 swedge blade at 60+/-2 HRC on 3.0 mm stock.
• Bead Blast blade finish - a uniform matte bead-blast texture that kills glare and hides carry wear.
• Silver Fluted Titanium machined with a groove-and-rivet flute pattern.
• Anodized thumb stud for fast, one-handed opening.
• Crossbar lock: ambidextrous, dirt-tolerant and finger-safe on closing.
• Ceramic ball bearing pivot that stays glassy for years.
• Steel pocket clip, tip-up, and a lanyard-ready rear.
• 87 g (3.07 oz) on a 6.69 inch frame - premium steel, honest carry weight.

Best Uses for the Firefly Ultra-S

• Daily pocket duty: mail, packaging, tags and food prep on a powder-steel edge.
• Office and urban carry where the fluted titanium frame reads as a machined showpiece.
• Weekend hiking and camping where corrosion resistance beats a semi-stainless workhorse.
• Collection display for the rose gold PVD or silver bead-blast finish pairing.
• Precision slicing tasks where the swedged tip and fine M390 edge earn their keep.

Frequently Asked Questions

What steel is the Firefly Ultra blade?
Bohler M390 powder-metallurgy stainless, hardened to 60+/-2 HRC. It offers first-class edge retention and corrosion resistance; sharpen it on diamond abrasives and keep prying loads off the fine tip.

What is the fluted handle?
Silver Fluted Titanium machined with a groove-and-rivet relief pattern - the flutes cut weight, add finger indexing and give the frame a machined industrial look.

How does the knife open and lock?
Press the anodized thumb stud and the ceramic ball bearing pivot swings the blade out one-handed; the crossbar lock wedges behind the tang from above and is fully ambidextrous and finger-safe on closing.

How big is it?
6.69" (171 mm) open, 3.7" (95 mm) closed, 2.99" (76 mm) blade at 0.13" (3 mm), and 87 g (3.07 oz) - a compact titanium folder with real blade stock behind the edge.

Rose gold or silver - which finish should I pick?
The rose gold PVD reads warm copper under lamplight; the bead-blast silver is the stealth option that hides scratches best. Both blades are the same M390 steel.

Bohler M390 vs. Common Pocket Knife Steels

Steel	Typical HRC	Edge Retention	Corrosion Resistance	Toughness	Sharpening Ease
Bohler M390 (this knife)	60-62	Excellent	Excellent	Fair	Hard
CPM-20CV	61-62	Excellent	Excellent	Fair	Hard
CPM-MagnaCut	62-63	Excellent	Excellent	Excellent	Moderate
CPM-S35VN	58-60	Very Good	Very Good	Good	Moderate
154CM	58-61	Good	Good	Very Good	Moderate
14C28N	58-61	Good	Excellent	Good	Very Easy
8Cr13MoV	57-59	Fair	Good	Good	Very Easy

Bohler M390 is an Austrian powder-metallurgy stainless in the same class as CPM-20CV and CTS-204P: roughly 1.9 percent carbon and 20 percent chromium-carbide-forming alloy deliver first-class edge retention and near-saltwater corrosion resistance. Hardened to 60+/-2 HRC, it holds a working edge for weeks of packaging and cord duty, but the dense carbide volume means sharpening wants a diamond plate and the fine apex can chip under prying loads. HRC figures are typical mill ranges, not a guarantee for any single blade.

Glossary of Key Terms

Trivisa
A Chinese knife brand building textured titanium folders around premium steels, with a clean in-house design language.

Firefly Ultra
Trivisa's compact M390 swedge folder: a 2.99 inch blade at 60+/-2 HRC, fluted titanium handle, crossbar lock, ceramic bearings, 87 g.

M390 Steel
Bohler's Austrian powder-metallurgy stainless in the 20CV/204P class: first-class edge retention, near-saltwater corrosion resistance, and a taste for diamond sharpening stones.

Swedge
A bevel ground along the blade spine. It lightens the profile, sharpens the tip's geometry and adds a distinctive silhouette.

Crossbar Lock
A spring-loaded bar spanning the handle that wedges behind the blade tang. Fully ambidextrous, keeps fingers out of the closing path, and among the strongest folder locks built.

Ceramic Ball Bearings
Hardened ceramic balls around the pivot. The action stays glassy for years, and ceramic will not rust or flat-spot.

Titanium Handle
Aerospace-grade Ti-6Al-4V scales: stronger than steel by weight, immune to corrosion, and warm-feeling in cold weather.

Fluted Titanium Handle
Titanium scales machined with groove-and-rivet relief. The flutes cut weight, add grip and give the frame a machined, industrial look.

PVD Coating
Physical vapour deposition: a hard, thin metallic-ceramic layer bonded to the steel. Rose-gold and black finishes resist scratches; edge wear is cosmetic, not structural.

Stonewash Finish
A tumbling process that beads the steel into a uniform matte grey, hiding carry scratches and killing glare far better than satin.

60+/-2 HRC
The Rockwell C hardness band the blade is heat treated to: hard enough for long edge life, still honest to sharpen at home with patience.

Who Should Buy the Firefly Ultra-S

• Buyers who want M390 edge retention in a compact titanium folder.
• Anyone who values an ambidextrous crossbar lock over flipper tactics.
• Collectors pairing the rose gold and silver variants as a two-knife set.
• Wet-climate carriers tired of wiping semi-stainless blades dry.
• Minimalists who like machined texture over plain slab scales.

Who Should Skip It

• Budget-first buyers - a 14C28N folder at a third of the price cuts cardboard just as well.
• Anyone who wants a fidget-style flipper or button action; this opens on a thumb stud.
• Users who need a pry bar; the fine M390 swedge tip is a slicer, not a lever.
• Ultralight chasers - at 87 g with 3.0 mm blade stock, the Sloth Ultra line is lighter.

Care & Maintenance

• Wipe the blade dry after every use; M390 is highly stainless, but the finish lasts longer when wiped clean.
• One drop of light knife oil at the pivot every two to three months, then swing the blade a dozen times so oil reaches the ceramic bearing.
• Sharpen on a diamond plate or CBN stone at 15-18 degrees per side; M390's vanadium carbides defeat ordinary aluminium-oxide stones.
• Work in light passes and finish on a loaded strop - heavy pressure on a 60+/-2 HRC edge just rounds the apex you set.
• Do not pry, twist or use the tip as a screwdriver; the fine M390 apex can chip under lateral load.
• Wipe anodized titanium scales with a dry microfibre cloth; the colour is a surface oxide, so keep solvents off it.
• Blow lint out of the crossbar-lock channel before oiling; grit under the lock bar is the usual cause of a gritty action.
• Check the body and clip screws every few months with the correct Torx driver; vibration on a keyring or pack can back them out.
• Store the knife closed and dry, never sealed in a damp pouch against the steel.