Screenshot by Nick Statt/CNET

Before the Apple Watch, there was the Dole banana.

The world's largest producer of fruits and vegetables, Dole has sponsored the Tokyo Marathon since 2008 and supplied bananas to potassium-deficient runners throughout the race. The company's Japanese division has even printed runners' stats on the banana peel in previous races.

So it's only natural that Dole's ambitions have moved onto wearable tech, an industry flush with fitness bands, watches, smart shirts and eyewear, but terribly lacking in vitamin B6. Enter the Dole wearable banana wrist ... thing.

The "gadget" is essentially wired parts stuck to the inside of an opened banana peel, which is then stitched back together. Once strapped to runners' wrists, the bananas will show racers' times, tweets, heart rate -- and when to eat the next banana.

"The power source is a small battery connected to the wearable banana. Inside the battery there are ultracompact LEDs and other electronic components," said Hiromi Otaki, a senior manager of marketing at Dole Japan. Cryptically, he added, "These are the only details about the specs that we can tell you at the moment."

Wearable technology is shaping up to be the next big frontier in consumer electronics' dutiful efforts to sell us stuff. The worldwide market for wearable devices, including fitness bands and smartwatches, is expected to surge to $52.3 billion by 2019, up from about $4.5 billion last year, according to market tracker Juniper Research. The highly anticipated Apple Watch, due to ship in April, along with products from luxury watchmakers, fashion designers and tech companies could fuel that demand -- and it's already fueling wacky promotional campaigns riding the wearable wave.

Of course, no company will be able to replicate the magic that is the wearable banana. Two runners out of the 30,000 marathon participants on Sunday will be handed Dole's device in the morning. They will then be asked to run 26.2 miles with a banana on their wrist, presumably without eating it.