Prompt.cash is a smartBCH bridge that allows one way transfer of BCH to sBCH. I have not found it two way but it allows only one way if I am not wrong. For those who are new and want to invest into smartBCH tokens should use it. At the time of withdrawal you can use other bridges like : wagon.cash, hop.cash etc. You can check out the prompt.cash bridge here: https://prompt.cash/bridge #smartBCH