The meets are held over two days, with heat in the mornings and finals in the evening, with the noted exception of the Brazilian meets where heats have been in the evening with finals the following morning (hence the 3-day format).
The meets are held over two days, with preliminary heats in the morning, and finals in the evening. A noted exception to this style are the meets held in Brazil, where prelims have been in the evening with finals the following morning (and hence a 3-day format).