Kylie Cosmetics can't seem to keep its hugely popular Kylie Lip Kit by Kylie Jenner in stock - but maybe that's all part of its marketing plan. The brand keeps selling out, announcing a restock date - and selling out again.

The latest restocking happened on Monday, when Kylie announced on Instagram that the Lip Kits would be available again for purchase at 7 p.m. EST - and by 7:30 they were listed as "unavailable" on the brand's website, once again.

The next "restocking," which might be more accurately called a flash sale, is scheduled for later this month. The line will also be adding a new color to its lineup, purple, called Kourt K.

Every lip kit contains a matte liquid lipstick and a matching lip pencil, which are shown above. The lipstick is packaged in a vial, with a flock tip applicator. Kylie recently announced that she upgraded the applicator to make it more fluffy, and feel softer on the lips.

The kit's carton, shown above, features an eye-catching pop art design, created from an image of Kylie's own lips.