SPY Exchange Traded Fund (ETF) Credit Spread

http://blog.theoptionplayer.com analyzes an S&P 500 ETF short-term (one week) bearish option strategy. Investors could simultaneously:
Sell the 8-day SPY $110 call for .57 and
Buy the $115 call at .01
The difference between funds received and paid out is a .56 credit which we keep if the SPY ends next week below $110, but exit the position if the price rises above.