This apparatus is used to demonstrate that the liquid transmits equal pressure in all directions (Pascal’s Principle).
The apparatus comprising a glass cylinder provided with a piston plunger on one end and terminating in a spherical glass bulb on the other end. The bulb has small holes around its surface. On pushing the plunger inside with the apparatus filled with water, water is ejected with equal force from all the holes.

A great and simple tool for class demonstrations.