A bear put spread is a vertical spread where you sell a put at a higher strike and buy a put at a lower strike, both expiring the same month.
Apple at $150:
Maximum profit: $3 per share ($300) if stock falls below $150. Maximum loss: $7 per share ($700) if stock falls below $140. Breakeven: $147 ($150 - $3 credit).
Maximum Profit: Credit collected
Maximum Loss: Width of strikes minus credit
Profitable Zone: Below the sold strike at expiration
Use when bearish. The further down you expect the stock to go, the more profitable the spread if it gets there.
Related: Bull Put Spread, Short Put, Vertical Spread