My best space-saving beauty hack combines eyeliner, highlighter, lip liner, and eyebrow filler in one small pen

• When there are a lot of products in your beauty and makeup routine, it's easy to lose track of the one that you need.
• Alleyoop, a new beauty and personal-care brand that specializes in multi-functional products, makes a four-in-one makeup pen that solves these problems.
• The Pen Pal ($25) is a cleverly designed pen that contains eyeliner, highlighter, lip liner, and eyebrow pencil. I love carrying it when I travel because it combines my most commonly used products in one portable, space-saving tool.
• Right now, Insider Reviews readers can save 10% on their order by using the promo code "INSIDER" at checkout.

I live for efficient, cleverly designed products. If I can use a single product more than one way, then I can divert the saved time, money, and space to other things in my life.

Beauty is a prime area where I could do with more efficiency and clever design. I hate pawing through my makeup bag in order to find the product I need, and I hate repeating that process for the entirety of my routine. Whenever I'm on the go or I travel, I inevitably forget an important product because there are so many to keep track of and pack.

That's why a tool from a new beauty and personal-care brand called Alleyoop has been the most useful product in my bag as of late.

The beauty tool, explained

The Pen Pal ($25) puts four common makeup products in one compact, portable pen. The design idea it borrows isn't new — it looks and operates exactly like the retractable ballpoint multi-pens you might've used in school or the office. There are multiple spring-loaded cartridges housed in one pen, and when you want to use a particular color, you click down on that button. Click down on any of the other buttons in order to retract the current color.

The only difference is that instead of various pen colors, the Pen Pal holds various makeup pencils:

1. Eyeliner in black
2. Highlighter in a shimmery cool tone
3. Lip liner in mauve nude
4. Eyebrow Pencil in dark brown

Each of these highly pigmented formulas are paraben-free, vegan, and cruelty-free.

Why the Pen Pal is useful

While the Pen Pal is great for everyday use if you have limited bag or cabinet space, it's especially useful for travel and other situations where you're on the go. Since it holds four products in one, you have fewer products to mentally account for, pack, and make room for.

I usually go to the gym after work, and after the gym I often have dinner or drink plans. Every morning, I think ahead to all the clothing changes, skin-care products, and makeup products I'll need. Whether I'm in a rush or just have many other things on mind, I almost always forget a product I need. Sometimes it's a pair of socks, other times it's my eyebrow pencil. With the Pen Pal, I don't have to think about where my eyeliner, highlighter, lip liner, and eyebrow pencil are. One product is easier to remember to pack than four.

The Pen Pal also takes up less space (or, depending on what products you currently use, no more space) than four individual pencils. When you travel, you likely don't have a lot of space to work with, and you need to take advantage of opportunities for saved space whenever possible. I like that I can travel a little lighter with the Pen Pal and free up precious space in my purse or suitcase.

Again, this depends on what products you currently use, but the Pen Pal may also be more affordable than the total cost of the four makeup pencils bought individually. If you're trying to save money on beauty, the Pen Pal is cost-efficient in addition to being space-efficient.

Factors to consider about the Pen Pal

The Pen Pal isn't perfect. At the time of this review, it only comes with the four shades above. Alleyoop says these are "universal shades that work with all skin tones" but they may not be ideal for your particular needs or preferences. As one example: I happen to have dark brown hair, so the eyebrow pencil was perfect for my brows, but it could be too dark for other hair types.

The Pen Pal also isn't refillable. Alleyoop does say that it's working on making refills so you only have to reload the pen instead of buying an entirely new pen.

Ideally, you would be able to choose from and mix and match pencil shades to create your perfect Pen Pal, then refill them with these shades whenever you run out of product.

Despite these limitations, I still found the Pen Pal convenient and useful enough to warrant carrying it around. Alleyoop makes other multi-functional products, such as a four-in-one makeup brush and all-in-one razor, but the Pen Pal has the most potential for both everyday and travel use.