A Straight Flush is any 5 cards of the same suit in sequence.
This is the second highest poker hand than can be obtained.

If two players have Straight Flushes, the player with the highest value card in the flush wins.
If both players have the same value cards and only suits differ, depending on house rules
regarding suit priorities, the players split the pot.

Examples

 
Straight Flush using the Clubs Suit (example)

Straight Flush using the Diamond Suit (example)