We put M·A·C Studio Studio Fix Powder Plus Foundation to the ultimate test of seeing how long it wears and, not surprisingly, the formula lasts for 12 hours!A one-step powder and foundation that gives skin a smooth, flawless, even all-matte finish with medium-to-full buildable coverage and a velvety texture that allows skin to breathe. Long-wearing, colour-true, non-caking, non-streaking, non-settling/creasing, non-fading  all for 12 hours. Available in a wide range of colours. MORE INFORMATION Choosing the right shade of foundation can become a real mission. M · A · C Cosmetics finally delivers the secret. Each shade is identified by a letter and a number. The Number indicates how dark the shade is. The higher the number, the darker the shade. Between 4 and 20, the foundations are designed for fair complexions. Medium skin tones will have numbers between 20 and 40. Finally, darker complexions between 40 and 54. The Letter represents the undertone, ie whether warm or cold tones. If the color of your veins is green, your undertones are warm. If the veins are mostly blue or purplish, you have cold undertones. Finally, if you have both, your undertones are neutral. C = Cold NC = Neutral and Cold N = Neutral NW = Neutral and Warm W = Warm M · A · C Beauty Tips: When in doubt, always go for the lightest shade. This allows you to avoid any risk of demarcation!