Doppler and Gamma Doppler are knife finishes that come in several colour versions, called phases. Every phase carries the same finish name, so a common Phase 3 and a rare Ruby can turn up under the same item title. Knowing how the game tells them apart is what keeps you from overpaying, or underselling.
Where Dopplers come from
Doppler first appeared in the Chroma Case on January 8, 2015, as one of six new knife finishes alongside Damascus Steel, Marble Fade, Tiger Tooth, Rust Coat and Ultraviolet. Those first Dopplers were on the five original knives: the Bayonet, Flip, Gut, Karambit and M9 Bayonet. According to the Counter-Strike Wiki, the Spectrum and Spectrum 2 cases later brought the same Chroma finishes to the Huntsman, Butterfly, Falchion, Shadow Daggers and Bowie, and the Prisma Case brought them to the Navaja, Stiletto, Talon and Ursus. The Fever Case, added in March 2025, gave the four Shattered Web knives Chroma finishes too.
Gamma Doppler followed in the Gamma Case on June 15, 2016, again on the original five knives. The Operation Riptide Case in 2021 put Gamma finishes on the second generation of knives. There is also one gun with phases: the Glock-18 | Gamma Doppler from the 2021 Train Collection. The Classic Knife and Kukri Knife have no Doppler finish.
The phases
Each phase is a separate paint kit in the game's item data, with its own Finish Catalog number. The colour descriptions below are broad, and individual knives vary.
| Finish | Phase | Finish Catalog | Typical look |
|---|---|---|---|
| Doppler | Phase 1 | 418 | Dark, mostly purple with some pink |
| Doppler | Phase 2 | 419 | Heavy pink with purple accents |
| Doppler | Phase 3 | 420 | Largely blue with hints of green and purple |
| Doppler | Phase 4 | 421 | Blue with black areas |
| Doppler | Ruby | 415 | Red throughout |
| Doppler | Sapphire | 416 | Blue throughout |
| Doppler | Black Pearl | 417 | Deep purple and black |
| Gamma Doppler | Phase 1 to 4 | 569 to 572 | Four different mixes of green and blue |
| Gamma Doppler | Emerald | 568 | Green throughout |
A few models use their own numbers. The game files give the Butterfly Knife and Shadow Daggers separate numbers for some phases (617 to 619), the Talon Knife its own Doppler block (852 to 855), and a separate Gamma Doppler block for the Glock-18 (1119 to 1123). When you check a phase, look up the numbers for that exact model.
Phase is not the pattern seed
This is the point most often misunderstood. In the game files, all seven Doppler paint kits share one display name, "Doppler", but they are different finishes underneath. The phase is fixed by which paint kit the knife received, not by its pattern number.
The paint seed still matters within a phase. It moves the colours around the blade, so two Phase 2 knives can look quite different, and Hotspawn's guide advises checking the pattern because some Phase 4 copies show much more black than others. A very blue Phase 4 is still a Phase 4, though, and a very dark Phase 1 is not a Black Pearl. The Finish Catalog number settles it. The pattern index guide explains what the seed does in general.
Float works the usual way, but within a narrow window. Every Doppler and Gamma Doppler knife phase is capped at 0.00 to 0.08, so they only exist in Factory New and Minimal Wear. The Glock-18 version is the exception, with a range of 0.00 to 0.50 that reaches Battle-Scarred.
The finishes did shift slightly in the move to Counter-Strike 2. Valve's notes for May 24, 2024 include a fix for the appearance of Doppler, Gamma Doppler and Marble Fade, so older screenshots may not match what you see in game today.
Rarity and value
Valve does not publish the odds of each phase. Hotspawn notes that the Black Pearl is generally considered the rarest, based on how often it shows up on trading sites, while the real figures are unknown.
On value, the picture is clearer for the numbered phases than for the gems. Phase 2's pink look has made it the most expensive of the four standard phases, according to Hotspawn. Among Ruby, Sapphire and Black Pearl, guides disagree on the order, and it varies by knife model, so check recent sales for the exact knife, phase and wear rather than relying on a general ranking. On the Gamma Doppler side, Emerald plays the role the gems play for Doppler: it is the solid-colour version collectors chase.
Checking the phase before you trade
- In game: inspect the knife and open the information panel. The Finish Catalog line gives the phase number; compare it with the table above.
- From an inspect link: the paint index in the link is the same number, which is how third-party tools show the phase.
- On listings: don't rely on the title alone. Steam Community Market names don't include the phase, so a listing called Doppler could be any of them.
On CS2Sell, the Doppler phase filter on Buy lets you browse a single phase instead of scrolling through every Doppler listing for a knife.