I previously asked this question What type of screw is this, How to remove this screw?
and somebody pointed out it was a t30 torx bit.
Here is my t30. I notice both ends of the key are different as per pic. Is one end or the other designed for the screw in the pic? A torx extension on a ratchet will only have one end why do my keys have two and the non circle star seems to be bigger.