Toilet fly, aka WC stickers, in the toilet improves the aim of all boys, big and small. We have them in rolls of 10, 30, 100 and 500 pieces. Known from a study done by a Dutch airport where the "marksmanship" was significantly improved by the fly in the toilet bowl. Attach the fly on a dry bowl and let it sit overnight before flushing or cleaning.
Flies for urinals are 25 mm in diameter