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Why Every Gadget Feels Like Shark Dick

An investigation to the strange feel of thermoplastics that has come to dominate our interaction with electronics.

​A friend of mine recently bought a new vaporizer pen. The friend shall remain nameless, as will the vaporizer, because the observation said friend brought to my living room, vaporizer in hand, was universal. "Feel this," he said, proffering the thing. "Feels like shark dick."

It did. Level with where it was meant to be held, the vape was sheathed in a thin layer of silicon rubber, a material which feels—to the untrained hand—like the most intimate membrane of the sea.


This texture is somewhat undefinable. It's variably described in plastics industry literature as "silky" and "soft-touch," but the way my friend's vaporizer felt wasn't new to either of us, nor is it likely unfamiliar to you. Shark dick, if you will, is everywhere. My iPhone case is made of the stuff, as are the buttons of all the remote controls in my house, the ridges of my earbuds, and my FitBit wristband. Start groping and you'll find instances in every room of your house.

I'm using "shark dick," of course, as an umbrella term, under which fall a variety of texturally similar materials: silicone, thermoplastic elastomers, polyurethanes, and rubbers. These share physical properties—hydrophobia, biocompatibility, durability, heat resistance, grippiness—that make them highly desirable for consumer applications from design and engineering standpoints alike. And while not all these materials are created equally, they all provoke the same reaction.

They practically beg us to touch them.

I often find myself touching my FitBit wristband, much as someone might idly fidget with a nice watch or a piece of jewelry; it simply feels nice, its hard polycarbonate clasp snipping into a rubbery divot, the particular resistance, somewhere between sticky and sleek, the band offers to my touch. Designers of wearables understand this intuitively. The more welcoming to the touch a device is, the more wearing it becomes second nature. The more it warms to use. The more it feels like second skin.


Wearable fitness trackers are prime shark dick: the FitBit, Misfit Shine, the Jawbone Up, all made of Thermoplastic Polyurethane, or TPU.

These materials are industrial design shorthand for touch: as on my friend's vaporizer pen, they show us where to grip, invite us to push buttons, and demand to be worn close to the skin. ​Yves Béhar, Chief Creative Officer at Jawbone, calls the Thermoplastic Polyurethane used in their ​UP fitness tracker "a friendly material," which "feels rich on the skin, doesn't get too cold and takes body heat."

In this sense, the increased popularity of these elastomers at the consumer level isn't surprising. As the points of contact between our selves and our technologies become ever more intimate—as we begin to wear rather than use our tools—the contours of hardware soften, shrink, and grow velvety. Among the largest consumer markets for Thermoplastic elastomers? ​Sex toys.

Of course, when it comes to sex toys, touch is important, if not essential, to a successful design experience. But this isn't the only category in consumer tech that is beginning to seriously consider handfeel, nor are plastics the only avenue catering to our sense of touch. Most of what we touch every day aren't shark dicks, after all, but screens—planes of glass and LED. And a tremendous amount of effort and research is currently going into communicating more tactile information through them.

A couple of years ago, ​Disney Research presented ​an algorithm for translating 3D information into tactile sensations on flat screens by modulating friction forces between the finger and the surface. Which is to say: they devised a technology which makes 2D planes feel textured by tricking the friction-sensitive receptors in the skin. The Disney algorithm fakes resistance, which is what makes touch satisfying. And satisfying touch is key to snaring consumers.


Are we having fun yet? Breakdown of Thermoplastic Silicone Vulcanizate via Dow Corning's website.

Doug Ebert is the product development manager for Ultimate Ears; he's on the team that built ​Ultimate Ears' BOOM and MEGABOOM, "life-proof" mobile bluetooth speakers explicitly designed to invite touch. They are colorful and grippy; both use ​Dow Corning's industry standard shark dick, TPSiV—a hybrid of thermoplastic urethane and cross-linked silicone rubber—in the body of the design.

"We think people want to feel more than hard plastic and metal grilles on their speakers," Ebert explains, "we wanted to use materials that invited people to want to touch and interact with our product. Each part was prototyped in many textures and different durometers to get it just right."

When you talk to designers who work with plastics on an industrial level, you hear a lot about ​Shore durometer, which is the scale by which the hardness of plastics is measured. Shore measurements are taken by stamping a standardized presser foot onto the material and measuring the depth of the indentation left behind. A rubber band has a Shore measurement of 25 A; a hard skateboard wheel is 98 A. Wristbands for fitness trackers hover in the 80-85 A range, soft to the touch, but sturdy enough to stay clasped around the wrist. Dow Corning's TPSiV ranges between Shore A 50 and 80, depending on its intended application—softer for wearables and earbuds, harder for accessory cases and buttons.

Left, silicon putty. Right, a Shore Durometer. Both images via Wikimedia Commons.

But hardness and texture are two different things. Even a hard plastic can be made to feel soft and rubbery, through the use of soft-touch coatings and paints, or through a texturing process called EDM, or ​Electrical Discharge Machining. Plastics companies issue texture books to designers, containing sheets and sheets of swatches in varied finishes, glosses, textures, and grains.


Tim Golnik, the VP of Product and Design at ​Misfit, which makes a fitness tracker called the Shine—a sleek aluminum puck nestled in a TPU wristband (durometer 85 A, in case you were wondering)—showed me one these texture books via Skype. Some of the panes of plastic were matte and nubby, others so glossy I could see my own reflection through the camera. "We can texture a band one way and someone will say it feels cheap; we can texture the exact same band in a different way and the same person will say it feels luxurious," he said. "The closer you get to feeling like silk, or velvet," he explained, the better.

We are entering the era of Peak Shark Dick. The Apple Watch's cheapest iteration,​ its "Sport" model, comes in a range of colorful wristbands made of a custom high-performance fluoroelastomer. The custom fluoroelastomer hasn't received as much media attention as Apple's other materials innovations for the watch—​their proprietary new alloys of aluminum and gold—but it will soon drape the wrists of millions, resisting their sweat, compelling their touch. Apple's website copy describes the material as "smooth" and "dense." It is the most populist of the Apple Watch materials.

Apple's custom fluoroelastomer Apple Watch sport band. Image via

Apple might have been the first major consumer electronics company to consider texture in its hardware design—its 1999 line of ​clamshell iBook laptops were paneled with colorful rubber—but shark dick-esque materials have been around since early computing. The ​Sinclair ZX Spectrum, a home computer that sold millions in the UK and Europe in the early 1980s, came equipped with a rubber keyboard that critics compared to typing on "dead flesh." The ​IBM PCjr, released in 1984, had rubber chiclet keys which reportedly felt like "massaging fruit cake." All suitable, and more appropriate, analogues than the euphemism I have been using.

But dead flesh keyboards are elementary stuff. According to Golnik, the squishy future is bigger and more far-reaching than that. For one, the Objet 3D printers industrial designers use to prototype things like wristbands actually print using similar thermoplastics as the final product, so designers can simulate different durometers and work easily with familiar materials from conception to production. Designing tactile all-in-one components that conform to the body will only get easier and more accessible.

More importantly, however, as electronic components become more flexible and less susceptible to heat, thermoplastics, silicones, and rubbers will really hit their stride, becoming a dominant material in a new world of tactile, wearable, and intimate consumer electronics. "It's going to take the electronics a while to catch up," but when it does, "you'll see more integration, less wall thicknesses, thinner devices using this kind of material and integrating it in a better way," says Golnik.

An irrelevant coda to this story is that ​sharks don't have dicks. They have two tight rolls of cartilage that biologists call "claspers," designed to grip lady sharks into place. Considering that one of the high virtues of the material my friend so flippantly called shark dick is its grippiness—it doesn't seem that ill-placed a neologism after all.