The default killstreak weapon only has a kill counter. If you want to get different cosmetic effects for your gun, you need to use a specialized killstreak kit.
Specialized Killstreak Kit TF2 - is the second tier of the killstreak kit that players can apply to their weapon. The upgraded weapon has a kill counter, color sheen, and a unique cosmetic effect.
Find the best specialized killstreak kit offers on DMarket marketplace, upgrade your weapon, and become a unique player on the server.