This is a Newman twist-action mechanical pencil. It's 13.2mm long. You twist the metal part that looks like a cap to advance the lead. Twisting it in the opposite direction advances a different color lead. If you continue twisting in the same direction, after the lead is fully extended, it retracts and the other lead advances. Pulling out the metal part reveals an eraser, and pulling out the eraser reveals replacement leads. The lead diameter is 0.9mm, and the red lead is more of a pink color. It has seen little use and is in good condition. The mechanism works well, and it writes without any problems.