function tune(uint endAt_,
                uint hardCapWei_,
                uint lowCapTxWei_,
                uint hardCapTxWei_) onlyOwner isSuspended public {
    if (endAt_ > block.timestamp) {
      endAt = endAt_;
    }
    if (hardCapWei_ > 0) {
      hardCapWei = hardCapWei_;
    }
    if (lowCapTxWei_ > 0) {
      lowCapTxWei = lowCapTxWei_;
    }
    if (hardCapTxWei_ > 0) {
      hardCapTxWei = hardCapTxWei_;
    }
    require(lowCapTxWei <= hardCapTxWei);
    touch();
  }