HKATS generates derived order from the price of the outstanding Standard Combination Order and the prevailing market price of each individual leg. In addition, user can enter 'Day', 'Fill-or-Kill (FoK)' and 'Fill-and-Kill (FaK)' order for standard combination series, while Block Trade is not allowed to be executed. As all the combination series expire and rebuilt on a daily basis, no 'Good Till Cancel (GTC)' order is allowed.