The pullet carpet shell is yellowish-white to greyish-brown, rhomboidal in shape with concentric growth rings and fine radial lines. It has yellow or reddish-brown markings similar colour to hen's, hence the name. The inside of the thick shell is glossy white often with purplish markings to one side. The pallial sinus extends at least half the length of the shell. Size up to 2 inches (5 centimetres). It is common all around the British Isles.