@amir I strongly disagree that the battery hatch comes off easily by simply pushing the tip of a screwdriver towards the center of the Twist, especially with the typical angle of a small flathead bit. There is a certain finesse to it; I have to "dig" out the hatch after releasing the catch. Maybe if you happen to have exactly the correct size implement, it would be easy. I have seen a lot of battery hatches over the last half century, and regardless of what design constraints you may have had with the Twist, there must be a better way to have done this.