Last year, Benefit Cosmetics released its first liquid foundation, and now the beauty brand is following up that debut with the Stay Flawless 15-Hour Primer (£25). Packaged in a convenient stick form, this creamy balm should be applied directly to your skin, or use a brush to get more even coverage. Either way, you'll end up with a poreless complexion and an invisible finish. While it's sweat-resistant, this primer is not a mattifying formula; your complexion will look dewy yet not shiny. Watch it hold up to an extralong workday, an afternoon at an outdoor concert, or even a backyard barbecue. Heat wave? What heat wave?