What Barbie and LEGO teach us about watch straps
Founder & CEO, Smartlet - CentraleSupelec engineer - Concours Lepine 2025, Awarded - CES 2026
Contents
Some of the most loved objects of the last century were sold half finished, on purpose. A doll arrived with almost no clothes, and a bag of plastic eyes and ears left the potato to you. Each one was a platform, and the fun lived in the parts you kept adding. Watch people play the same game with a straight face, and far more slowly than it deserves.
- Barbie sold the wardrobe. The doll cost $3 in 1959; her 22 launch outfits were sold separately, from $1 to $5.
- Standards outlive products. LEGO bricks from 1958 still connect with today's, and KitchenAid hub attachments from the 1930s fit modern mixers.
- A watch has the same logic. One watch on a different bracelet reads as a different object, as long as the change takes seconds rather than a towel and a spring bar tool.
- 10 seconds, under 5. With watch adapters fitted, a Smartlet bracelet changes in 10 seconds, and the watch itself in under 5.
- Connected accessories. A smartwatch or a Whoop goes underneath, against the skin, and the Clasp takes its place for the evening.
Three dollars for the doll, the rest for the wardrobe
Barbie went on display at the American International Toy Fair in New York on 9 March 1959, in a black-and-white striped swimsuit. Ruth Handler, who had co-founded Mattel, sold her as a "Teen-age Fashion Model", and Mattel's designer Charlotte Johnson drew the clothes. About 350,000 dolls sold in the first year (sources: Wikipedia, History.com).
The swimsuit is the clue. A doll that arrives almost undressed asks for a wardrobe, and Mattel designed Barbie to keep selling garments long after the doll was bought. Children understood the rest on their own: change the outfit, and when the story needed more, change the doll.
A potato you brought yourself
Mr. Potato Head went further. When Hasbro launched him in 1952, the box held plastic eyes and ears on pushpins, meant to go into a real potato from your own kitchen. A plastic body only joined the box in 1964, partly because parents had had enough of forgotten vegetables. On 30 April 1952 he also became the first toy advertised on television (source: Wikipedia).
The lesson for a watch collector is oddly exact. The most important part of the toy was the one you already owned.
A brick from 1958 still fits
The LEGO brick was patented on 28 January 1958, and a brick from that year still connects with one bought this morning (source: Sigmalive). Sixty-eight years of new sets, and the studs on top never moved.
KitchenAid did the same in the kitchen. Every stand mixer since the Model K carries one attachment hub on its front, and hub attachments from the 1930s fit today's mixers (source: Wikipedia). People hand down a pasta roller the way others hand down a watch.
The product changes and the interface stays. Get the socket right once, and every new part adds to what people already own instead of replacing it.
Why most watches never get dressed up
A watch has its own standard socket, the gap between its lugs, measured in millimetres since long before LEGO. Every collector knows the theory: the same watch on a different strap becomes a different object at dinner. Leather for the office, and the striped NATO strap that has outlived the soldiers it was made for.
The practice is less glamorous. A towel on the kitchen table, and two spring bars that would rather fly across the room than go back in. So the change happens twice a year instead of twice a day, and the drawer fills with straps that never leave it. Barbie's clothes came off in seconds. Children changed them all day.
A new bracelet in 10 seconds, a new watch in under 5
On a Smartlet, the slow part happens once. Two watch adapters take the place of your watch's spring bars, a first fitting of under 10 minutes with the spring bar tool included in the box (set up your Smartlet shows each step). After that, the bracelet sides lock into the watch adapters, and changing the bracelet takes 10 seconds, by hand.
Keep a black matte PVD bracelet for the evening next to a steel one for the day. The additional strap exists for exactly this: a second set of bracelet sides in another colour or design, changed in the time it takes to decide.
And like Mr. Potato Head, the platform welcomes what you already own. Give each of your watches its own pair of watch adapters, and switching from one to another takes under 5 seconds. Watch adapters exist from 18 to 24 mm, with 23 mm coming soon. The lug width guide and the compatibility index tell you which of your watches can join, and the lug styles guide explains the few that cannot.
Accessories, now connected
Barbie's accessories came one tiny handbag at a time. The modern wrist has its own: the smartwatch, or the recovery band that wants to stay on through the night.
On a Smartlet they sit underneath, against the skin, in the central part of the bracelet, while the watch stays on top. The box carries the Apple Watch adapters in both sizes and the Whoop 5.0 and MG adapter. Fitbit Charge 5 and 6 have theirs too, and other smartwatches take the standard smartwatch adapters.
Accessories also come off. For a dinner where the watch should be alone, the Clasp closes the bracelet in place of the smartwatch. For the night, it closes in place of the watch, and only the tracker stays.
Nobody ever made Barbie choose between a new outfit and a new handbag. Your wrist should not have to either.
Playing with a watch, as a grown-up
A strain of watch talk treats dressing a watch as a slightly embarrassing hobby, the horological equivalent of owning forty ties. I find that backwards. Every object in this essay was built for play, and the adults who grew up with them now buy attachments for a decades-old mixer hub without a second thought.
Play is also how you find out what a watch can do. A diver on black PVD can sit under a cuff after all. You learn a watch by dressing it a few times, and by composing the whole wrist rather than one piece of it.
Nobody calls that childish when a stylist does it. They call it a look.
Smartlet, awarded at the Concours Lepine 2025 and selected for CES 2026, gives the wrist its wardrobe back.
Barbie is a trademark of Mattel, Mr. Potato Head of Hasbro, LEGO of the LEGO Group and KitchenAid of Whirlpool. This independent essay has no affiliation with any of them, and none has endorsed it.
