OpenDime is a type of hardware wallet that stores bitcoin. The device is in the form of a small USB stick that can be plugged into any device with a USB port. When plugged in, it generates a QR code and text files that display the user's Bitcoin address. Using the QR code, users can check their balance, payment address and, once unsealed, their private key. The device can be unsealed at any time using a push pin, which reveals the private key and enables the user to start spending their bitcoin online.

OpenDime can be used as a secure way to store and spend small amounts of bitcoin, and it's a unique alternative to traditional paper wallets, software wallets and hardware wallets which are more complex to use and also costlier. It's a simple, straightforward, and easy-to-use device that can be used by anyone, even those who are new to Bitcoin.

Opendime has generally received positive feedback from its users. The device is commended for its ease of use and portability, as well as its added security features. Users appreciate the tamper-resistant seal and the fact that the private key is never exposed to the internet, providing an additional layer of security for their bitcoin.

Users also appreciate the low cost of the device, which makes it accessible to a wider range of individuals and is an appealing alternative to more expensive hardware wallets. Overall, Opendime is considered a secure and user-friendly way to store and spend small amounts of bitcoin.