What is your problem? Just sayin' that many self-extracting crank bolts have only one hex opening. The outer ring threads in using a pin spanner. In many the two threaded members are permanently joined together. You use the pin spanner to install or remove the entire self-extracting bolt while leaving the crank arm attached. You use the allen wrench to actuate the self extracting feature and remove the crank arm. What is so hard to understand?