Finding the proper screwdriver/wrench

My Zune Zune 4 GB player has small screws that need to be removed to change out the battery. According to battery replacement info on the net they say a t4 screwdriver is needed. I bought one. It does not fit. The screwdrivers I see have 6 prongs on them.

The screws on the player have 3 prongs. Can you tell me or point me to the proper screwdriver/wrench