Beacon was designed by AirGap to connect Tezos dApps with Tezos wallets. It makes it possible to connect wallets with dApps by simply scanning a QR code to establish connection.
AirGap is a wallet application that can turn your old smartphone into your new "hardware wallet". So AirGap is not your average wallet. It works like this: if you have a mobile phone that you use for daily use, and an additional (possibly old) phone, then you can use your daily phone as a wallet for average payments, and your old phone as an off-line hardware wallet. This gives an extra level of security for larger amount funds that you can store on your off-line device. While you keep a smaller amount of funds on your daily phone.
With AirGap’s two device approach, you can sign transactions completely offline on a device without any network connectivity with the AirGap Vault application and broadcast them with your every-day smartphone with the AirGap Wallet app.
The reason to do so, is the fact that anything that is connected to the internet, is a possible security risk. You might not want to store your private keys on a device like that. Not your phone, not your tablet, not your computer. This is why you should consider storing larger funds on hardware wallets like for example Ledger. AirGap offers a hardware wallet solution where your old mobile phone can function as a hardware wallet. The reason you would use an old mobile phone would be the fact that your hardware device should not be connected to the internet. So the only use for this phone would be to function as a hardware wallet. So if you have an old phone laying around, this would be a great way to give it new purpose. You can obviously buy a new phone and use that, but then you would be cheaper off with a Ledger Nano or other hardware wallets that are cheaper than a new phone. So, great solution for the creation of a hardware wallet without needing to spend money on a new device. You can store several cryptocurrencies on your AirGap wallet. AirGap supports Tezos' XTZ, and tzBTC: the BTC-backed stablecoin on Tezos. Also BTC, ETH and a few other coins are supported.
AirGap runs it's own baker (Tezos node), which means you can delegate the XTZ you hold on AirGap and earn staking rewards.
New to Tezos? Read this full introduction to Tezos.