Don't use screwdrivers, you will ruin it. No tool for that needed. Squeeze the front and back sides in your picture on the left side of the ring which will oval it and make the 2 tabs on top and bottom have less grab. It will take some wiggling and one side will come unhooked. Keep squeezing and working it and you will get the other side and it will slide off easily. You will get a squirt of fuel since it is under pressure but no big deal. Takes about 3 seconds but I've done hundreds of them.