DESCR("minimum data transfer amount", "%g", min_transfer_amount);
DESCR("maximum data transfer amount", "%s",
h.val_or_string(max_transfer_amount, "no limit"));
DESCR("minimum data transfer amount", "%g", min_transfer_amount);
DESCR("maximum data transfer amount", "%s",
h.val_or_string(max_transfer_amount, "no limit"));