GUILT-FREE GLAMOUR!® Shocking Blue AMPLIFIED is a dark cobalt blue hair dye. For best results, we recommend lightening hair to a very light cool-toned level 9 blonde or lighter. All semi-permanent blue hair colors can interact with yellow tones in bleached hair to create a green tint so make sure to do a strand test prior to applying all over to ensure you get the results you want! If you'd like to avoid a possible green undertone, you can add in a purple shade like Purple Haze to offset this effect. When mixed with Pastelizer, Shocking Blue becomes a gorgeous steely, blue-grey pastel shade! Our Amplified Formula contains up to 30% more pigment than their classic counterparts! WEAR IT LOUD!® Details:Style: Amplified Semi-Permanent Hair DyeColor: Shocking BlueColor Description - Dark Blue Hair DyeVolume: 4oz / 118mlIngredients: Vegan Friendly, PPD Free!Additional Features: Benefits of Conditioning Hair, Resealable Tub For Longer Use, Comes With Instructions, Longer Lasting Formula with 30% More PigmentDuration: up to 6-8 weeks with proper hair care For Best Results: See Instructions Tab