Selling the short-term options in a Double Calendar strategy obligates you to deliver the underlying asset at the strike price if the options are assigned.

The goal is for the short options to expire worthless while holding longer-term options, which benefit from time decay and potential volatility. This strategy has limited profit potential if the asset stays near the strike price, but substantial risk if the price moves significantly in either direction.

The reason some traders use this strategy is that it can be profitable in low-volatility markets, as the short options lose value over time. If the market moves against you, it's important to have a risk management plan in place, including a stop-loss strategy, and to monitor the position carefully as it unfolds.