Physical bitcoins don't work. Bitcoin is digital money. When people put bitcoin onto metal coins, they get a novelty item at best, a scam at worst. Most designs etch the private key into the metal, then cover it with a sticker or similar protection. The manufacturer knows the private key. If you hand it to someone for payment, that person must trust you didn't spend the bitcoin or copy the key. Bitcoin operates in cyberspace. Using metal to store a private key defeats the purpose, like publishing Wikipedia as a hardcover. Converting from a new format to an old one kills the advantages and creates new problems. CoinKite's OpenDime breaks this pattern. It sits between a hardware wallet and a physical bitcoin, occupying a new category. OpenDime is a near-disposable hardware wallet with one function. You can check its balance and verify the private key never left the device, from current or past owners. You load it multiple times, but empty it once. It's a USB stick in a clear acrylic case with components visible underneath. Two LED lights and electronics sit exposed. The circuit board has a rectangular hole down the center. A peninsula runs through it, held in place by glue. At its tip sits a small golden padlock engraving. The physical design has appeal. Small size, golden contacts, bare circuitry. It reads cyberpunk. That exposed approach comes with a price. Two sample units arrived fully encased in glue. One sample had a small hole on the end, big enough for dust and liquids to seep in. CoinKite keeps costs down by skipping an enclosure. The gluing technique merits improvement. The peninsula is what sets it apart. Plug it into a computer the first time and it appears as a standard USB drive. A few files and instructions load. No key pair exists yet. OpenDime asks you to add 256KB of data. The software generates a random key pair from that. Now it becomes a bitcoin piggy bank. Plug it in and the LED flashes green. Your private key hasn't been touched. In a computer, you see the public key and a QR code. You can verify the private key remains secure. CoinKite provides verification tools. Any bitcoin signature software works too. To access the bitcoins inside, you snap off the peninsula. LEDs blink red now. The files change. The private key appears. The real selling point is anonymous transactions without the blockchain. Rather than sending bitcoins, OpenDime lets you hand over a verified, secured private key. Hardware wallets have advantages. You can use them infinite times. OpenDime works once. But OpenDime wins on one dimension. You load it with bitcoin and sell it. The buyer knows the seller never saw that private key. It works this way in practice. The peninsula needed effort and pliers to break off. Having it tough beats having it snap too quick. At $15 per unit including shipping, or lower for bulk orders, these aren't true disposables. You won't load one with a few dollars or even $20 worth of bitcoin. At that price, anything above half a bitcoin becomes viable. The company website frames it this way: "We expect most Opendime units to be loaded once, probably with a 'round number' of bitcoins, and unloaded exactly once in their lifetime. It's impossible to know what's happened in the meantime—just like a gold coin that has passed through many hands over the years." I see it as a bitcoin savings tool. Money locked away, requiring destruction to access. Like a piggy bank with no removable bottom. The only way out is to smash it. The $15 cost prevents impulse spending without being prohibitive. I gave up on physical bitcoin representations long ago. Hardware wallets serve essential functions, and any holder with serious bitcoin needs one. But something that lets you make a secure purchase by handing it over, that's different. OpenDime offers something new. It created a product category that didn't exist. It's bitcoin's first successful connection between physical and digital money. My single gripe is the cheap gluing technique. That's minor. The price keeps these from being mass-giveaway items. That doesn't appear to be their target. No one buys a drink with an OpenDime. Big purchases, cars, houses, anything making $15 trivial, fit the use case. It also works for teaching savings habits to kids or adults prone to spending. It's a bitcoin-era piggy bank for the digital age. [Note: Coinkite provided samples for this review]