Clay Targets or Clay Pigeons as they are often known, are discs of pitch mixed with ground limestone. they are fragile so that they shatter when hit by small pellets or shot from a shotgun cartridge. There are many types, the main ones you will see at shooting grounds are:
Standard: 11cm diameter, 2.5cm thick in black orange or fluero yellow.
Midi: Same shape as the standard but with a diameter of only 9cm.
Mini: Only 6cm in diameter and 2cm in height.
Battue: A thin, flat clay 11cm in diameter which flies very fast and falls away suddenly.
Rabbit: 11cm thicker flat target in the shape of a wheel designed to run along the ground.