Put Calendar

A strategy using calls where the trader sells a lower strike call, buys a higher strike call and another higher strike call.

A spread where more options (calls or puts) are bought than sold. (the opposite of a Ratio Spread).

A net debit spread only using puts where the trader buys a higher strike put and sells a lower strike put. The higher strike put will be more expensive, hence the net debit. Bear Put spreads have limited risk and reward and are more profitable as the underlying asset falls.