One CBOT mini sized Dow futures contract of a specified contract month.

Minimum price fluctuation is one point ($5).  For example, an option with a premium of twenty (20) points has a value of $100.

Twenty 100 index point intervals up and down from the futures price plus ten additional 200 point intervals above and below the highest and lowest 100 point intervals.

The first three consecutive contract months (two serial expirations and one quarterly expiration) plus the next four months in the quarterly cycle (Mar, Jun, Sep, Dec).  Serials will exercise into the first nearby quarterly futures contract.  Quarterlies will exercise into futures contracts of the same delivery period.

Unexercised quarterly expirations of options on mini-sized Dow futures shall expire at 7:00 pm Chicago time on the business day following the last day of trading.  Unexercised serial expirations of options on mini-sized Dow futures shall expire at 7:00 pm Chicago time on the last day of trading.

American style.  The buyer of a futures option may exercise the option on any business day prior to expiration by giving notice to the Board of Trade clearing services provider by 6:00 pm, Chicago time.  Options that expire in-the-money are automatically exercised into a futures position, unless specific instructions are given to the Board of Trade clearing services provider.

For standard quarterly option contracts:  The trading day immediately preceding the Final Settlement Day. Final Settlement Day is the third Friday of the contract month

For serial option contracts: The third Friday of the serial contract month.

Monday: Thursday 3:30 pm - 4:30 pm and 5:00 pm - 3:15 pm next day
Sunday: 5:00 pm - 3:15 pm next day
Quarterly futures/options: Trading can occur up to 8:30 a.m. on expiration day 
Serial options: Trading can occur up to 3:15 p.m. on third Friday of the contract month

Electronic: OYMC for calls, OYMP for puts

Successive 10%, 20%, and 30%