(1)  A filling aperture of a hot water bottle must be 18 millimetres or more in diameter.

(2)  If the filling aperture is less than 20.3 millimetres in diameter, the hot water bottle must be equipped with an integral filling funnel that –

(a) has a minimum capacity of 60 millilitres when a stopper is fitted; and

(b) extends beyond the height of the stopper.

(3)  In this clause –

integral filling funnel means a funnel that is designed to assist the safe filling of the hot water bottle.