futures option questions

Depends on specific contract. SPX options is 100x s&p; SPY options is also 100x but each "share" is only 1/10 the size of S&P, options on S&P Futures is 250x S&P, DJX is 100x but each share is only 1/100 DOW, DXL("Jumbo DJX") share is 1/10 DOW.... there are other contracts. can be confusing for beginners. there is also difference of Amecican style exercise and European style exercise, different expiration date and AM or PM. Check contract specifications on exchange websites.