Ursus Knife | Doppler Phase 4 (Ursus P4) was added to the game on March 13, 2018, alongside the "Seeing the Light" update. The skin is available in the "Prisma" case.
The blade of the knife is painted with metallic paints and adorned with a pattern of translucent wavy lines resembling smoke. The color scheme of the skin includes various shades of blue, brown and black creating gradient transitions. The handle remains unpainted.
Float Value of the skin ranges from 0.00 to 0.08, which makes Ursus Knife | Doppler Phase 4 available only in Factory New and Minimal Wear condition. At levels of wear close to the maximum, the knife has small abrasions located on the spine.
The pattern index affects the ratio of colors as well as the location of blue, brown and black areas. Pattern variations with a predominance of blue on the play side of the blade are titled “BTA Blue”. Knives with only blue color on the blade resemble Ursus Knife | Doppler Sapphire and are titled “Max Blue”.
The quality of Ursus Knife | Doppler Phase 4 is Covert. The skin has a StatTrak option and is close to phases 1 and 3 in terms of rarity. The skin belongs to the "Ursus Knife | Doppler" series.
Due to a relatively low price, Ursus Knife | Doppler Phase 4 became one of the most popular and common skins in the “Doppler” series.