M4A1-S | Blue Phosphor

M4A1-S | Blue Phosphor released December 3, 2020 as part of the Control Collection.

It originally released during the CS:GO era, before Valve's Counter-Strike 2 relaunch in September 2023 — its artwork, wear range, and source carried over unchanged into CS2.

It launched as a Classified-tier finish, with a Souvenir edition but no StatTrak™ version.

As a finish, "Blue Phosphor" is applied to the M4A1-S — the Counter-Terrorists' suppressed carbine, trading magazine size for reduced recoil and a quieter shot — and carries the pink rarity color every Classified-tier skin shares on the Steam Market and in-game.

That Classified classification places it one tier below the rarest Covert finishes, but above the more common Restricted-and-below skins most loadouts are filled with.

M4A1-S | Blue Phosphor only ships in 2 of the five wear conditions (Factory New, Minimal Wear) — there's no Field-Tested or Well-Worn or Battle-Scarred release for this finish.

As with every CS2 skin, lower float values look cleaner: Factory New copies (roughly below 0.07 float) show the finish at its sharpest, while Field-Tested and Well-Worn pieces make up the most commonly traded middle ground between mint and heavily worn.

M4A1-S | Blue Phosphor is part of the Control Collection rather than being unboxed from a traditional weapon Case — the Collection is not tied to any live drop mechanic, so trade-ups and the Steam Community Market are the main ways to acquire one.

Valve has never published exact Collection odds. The estimate above (1 in 1562, 0.0640%) applies the same rarity-tier cascade confirmed for Cases, giving a general sense of scale rather than a guaranteed rate.

Alongside the Normal version, this finish also has a Souvenir edition — there's no StatTrak™ counterpart.

Beyond that, there's no separate "phase" or pattern family tied to this finish in the site's data — it's tracked as a single fixed look across every wear condition it ships in.

As a Classified-tier finish, M4A1-S | Blue Phosphor sits among the more common pulls from the Control Collection rather than being a chase item — a straightforward, affordable way to add a M4A1-S skin to a loadout or collection.

Its Souvenir edition tends to trade at a premium over the Normal version, the same pattern seen across most CS2 skins with that variant available.

M4A1-S | Blue Phosphor has been part of the Control Collection since December 3, 2020, and like every CS:GO-era CS2 skin, carried over unchanged when Valve relaunched the game on the Source 2 engine in 2023 — the artwork, wear range, and source Case/Collection are the same today as they were before the migration.

It's one of 2 Classified-tier items in the Control Collection, out of 19 items total.

This is one of 46 M4A1-S skins currently listed on the site, spanning multiple rarity tiers.