Only stocks at this stage but I believe options are in the works. What gabra said about stops is incorrect. You can set a price range..............you specify a price below which you will sell with a lower limit. eg your order to sell TLS below $5 but no lower than 4.60 would read:
Sell ?? TLS shares if the prices reaches less then or equal to $5 with a limit of $4.60. That way if the market gapped you would still be filled at market as long as it opened above $4.59.