MAC RiRi Woo is a very cool-toned, medium-dark red with a matte finish. It is a limited edition lipstick that retails for $19.00 and contains 0.1 oz.
MAC RiRi Woo Lipstick ($15.00 for 0.10 oz.) is described as a "matte cool red [with a retro matte finish]." It's a deep, medium-dark red with strong cool undertones and a matte finish. MAC Ruby Woo is absolutely similar--it's very, very similar. RiRi Woo is inspired by Ruby Woo, but the difference is very slight--there's a noticeable difference in darkness and undertone when the two are swatched side-by-side, but applied, it is incredibly difficult to tell.
FURTHER READING: Formula Overview, which is a detailed review of the range as a whole.
Formulated to shade, define and showcase the lips, M·A·C Lipstick is available in every nuance of your favorite color and high-fashion texture. It's the iconic product that made M·A·C famous. AMPLIFIED CREME (A): Ultra-creamy. Quietly shiny. Color-packed! Hi-res: hi-impact. CREMESHEEN (C): Creme-based lipstick that imparts bright full color, with a soft and supple shine. FROST (F): Excellent color payoff with medium to high frosted shimmer-and-shine finish. LUSTRE (L): Demi-sheer with wet-look lustre finish. Very slick. Makes lips look soft, smooth, ultra-moist. MATTE (M): Pigment rich with intense color pay-off. No-shine, all matte finish. SATIN (S): Color-rich. Soft satin, semi-matte finish. Conditions while adding intense color.