The Irish half penny coin, designed by Percy Metcalfe, was the second smallest denomination of the pre-decimal pound. 

There were 480 half pennies in a pound.

It weighs 5.67 grams and is 25.5mm in diameter (1.005 inches) and 1.77mm thick.

It is made of bronze which is 95.5% copper, 3% tin and 1.5% zinc

It was fist minted in 1928 with the date split on either side of the harp 

and saorstát éireann (Irish Freestate) circling around until 1937 and then from 1939 until 1967 (the last year minted) éire

was on the left of the harp and the date was placed on the right of the harp