0 = Day (or session)
1 = Good Till Cancel (GTC)
2 = At the Opening (OPG)
3 = Immediate or Cancel (IOC)
4 = Fill or Kill (FOK)
5 = Good Till Crossing (GTX)
6 = Good Till Date
7 = At the Close
Many of these values are interesting. Most confusing is IOC ^ FOK. The IOC order can (but does not have to) be filled in full. If it cannot be filled immediately or fully, the pending part gets canceled (a partial execution is generated) by the market. It differs from a fill or kill order in that in fill or kill orders, partial executions are not accepted.