Pencil-A pencil is a writing implement or art medium constructed of a narrow, solid pigment core inside a protective casing which prevents the core from being broken or leaving marks on the user’s hand during use. Most pencil cores are made of graphite mixed with a clay binder which leaves grey or black marks that can be easily erased. Other types of pencils core are less widely used, such as charcoal pencils.

Stethoscope- The stethoscope was invented in France in 1816 by Rene Laennec at the Necker Enfants Hospital in Paris. it consisted of a wooden tube and was monaural. Laennec invented the stethoscope in 1816. He observed that a rolled notebook, placed between the patients chest and his ear, could amplify the heart sounds.

Tunneling Shield-A tunneling shield is a protective structure used during the excavation of large, man made tunnel. When excavating through ground that is soft, liquid, or otherwise unstable, there is a risk to workers and the project itself from falling materials and/or a cave in. A tunneling shield serves as a temporary support structure.