USP-S | Serum

Origin Story

The USP-S | Serum was introduced during The Arms Deal 2 update, adding one of the earliest high-tier finishes to the pistol lineup. Its design takes inspiration from digital camouflage overlays blended with anodized multicolored techniques, producing a reflective, liquid-like texture across the weapon’s surface. The bold red and dark graphite tones combine into a visually striking “chemical spill” aesthetic, giving the skin its aptly chosen name–Serum. As one of the original Classified-grade USPS skins, it reflects the era when Valve focused on metallic depth, realism, and layer-based finishes instead of loud thematic artwork.

Drop Chance

According to Valve’s official case rarity tiers and the contents of the CS:GO Weapon Case 2:

Rarity Tier: Classified

Tier Base Odds: 3.20%

Classified skins in CS:GO Weapon Case 2: 2

Individual Skin Drop Chance (base):
3.20% ÷ 2 ≈ 1.60% per case

StatTrak™ Variant:
StatTrak™ skins appear on roughly 10% of weapon drops:
≈ 0.16% per case for StatTrak™ USP-S | Serum

These odds apply to each individual case opening and do not improve over time. While the numerical odds per case are higher than Covert-tier items, Serum still relies on the relatively rare CS:GO Weapon Case 2 being opened, which limits the practical supply of new copies.

Skin Condition

Serum uses a limited anodized finish float range:

• Float Range: 0.00 – 0.25
• This means it can only exist in:
• Factory New
• Minimal Wear
• Field-Tested
• And cannot drop as:
• Well-Worn
• Battle-Scarred
• At low floats (0.00–0.05), the chrome underlayer is most reflective, creating a polished metallic sheen. As floats increase toward Field-Tested, the red digital pattern becomes slightly muted, particularly on the suppressor and slide edges, but the underlying structure remains crisp thanks to the finish type.

Model

USP-S | Serum is a CS:GO-origin (legacy) skin that remains fully obtainable and playable in CS2. Released with The Arms Deal 2 update, it is tied to CS:GO Weapon Case 2, which can still be opened, allowing new Serum skins–including StatTrak variants–to enter the market.

How to Obtain

USP-S | Serum is a CS:GO-origin (legacy) skin, but the CS:GO Weapon Case 2 remains openable in CS2, meaning the skin is still obtainable today.

You can unbox it from:

CS:GO Weapon Case 2
The Arms Deal 2 Collection

Due to the case’s age and reduced circulation, fresh unboxes are less frequent than modern cases, making high-condition Factory New and StatTrak™ variants comparatively rare.

Price Range

Because of its higher rarity and consistent collector demand, USP-S | Serum tends to sit at a mid-to-premium price point among legacy USPS skins.

Market value typically falls between:

$77.19 – $204.70

StatTrak™ Factory New holds the strongest premium due to extremely limited supply and the tight classification constraints of older cases.

Visual Theme

The Serum finish applies an anodized multicolored digital pattern over a chrome base, giving the weapon a layered metallic shimmer. Deep reds, dark grays, and subtle green undertones combine into a camo-like design that shifts under different lighting angles. The weapon’s silhouette is enhanced by the reflective surfaces, making the suppressor look almost liquid-coated. The result is a high-contrast, premium-feeling finish with strong presence in both first-person play and spectator views.

Player Rating

USP-S | Serum is appreciated by long-time collectors and players who prefer metallic, premium-feeling finishes over more stylized modern skins. Its early CS:GO heritage and Classified rarity give it added prestige among enthusiasts.

Rating: 4.17 / 5
Votes: 3