<a href="https://en.wikipedia.org/wiki/Binary_option#How_binary_options_work" rel="nofollow">https://en.wikipedia.org/wiki/Binary_option#How_binary_optio...</a>
Wikipedia explains a binary option as:<p><i>Binary options "are based on a simple 'yes' or 'no' proposition: Will an underlying asset be above a certain price at a certain time?" Trades place wagers as to whether that will or will not happen. If a customer believes the price of a commodity or currency will be above a certain price at a set time, he buys the binary option. If he believes it will be below that price, he sells the option. The price of a binary is always under $100.<p>Every option settles at $100 or $0, $100 if the bet is correct, 0 if it is not</i>