for good measure

Từ điển Oxford Advanced Learner 8th

for good ˈmeasure idiom
as an extra amount of sth in addition to what has already been done or given
•Use 50g of rice per person and an extra spoonful for good measure.
•‘I'm no good at puzzles. I can't even do crosswords,’ she added for good measure.
Main entry: ↑measure_idiom