The SOME BY MI Yuja Niacin 30 Days Miracle Sleeping Mask is a 2-in-1 sleeping mask that brightens and moisturizes skin while you sleep. Enriched with 70% yuja (citron) extract, which contains 3 times more Vitamin C than a lemon, to recharge and brighten for glowing skin. Niacinamide, arbutin and glutathione helps even out your skin tone, while 10 types of vitamins nourish and soothe your skin while you sleep.