There probably is a special tool. but all you need is a big wide screwdriver, or similar flat blade that will fit inside the housing, into the notches. Then, it is a simple counter-clockwise turning to un-screw the locking ring. You should find a rubber seal, amber cap,. and the bulb. The amber cap and gasket may be stuck and you might need a very thin hooked wire or similar to get behind the cap and pull it out. The bulb also is a bit difficult to get out. It is the bayonet type, meaning you have to push and turn counter clockwise to disengage the pins on the bulb from the locking slots on the case. A soft piece of hose usually does the job, as long as it is sufficiently sticky and does not slip on the glass of the bulb. Reverse process to install a new bulb, and then the fun of lining up the threads of the locking ring, with pressure from the internal spring pushing back! It is difficult to get it started and not cross-threaded. Good luck!