The answer to 'P-trap or P-trap' is that a P-trap and a U-trap are both common types of plumbing traps used in sinks, tubs, and other fixtures to prevent sewer gases from entering the home. The main difference is the shape of the trap. A P-trap has a curved 'P' shape, while a U-trap has a 'U' shape. Both traps work by creating a water seal that blocks odors and pests from coming up through the drain.
P-traps are the most common type of trap used in residential plumbing. They are easy to install, affordable, and effective at preventing sewer gas backups. U-traps are less common but can be useful in certain situations, such as when space is limited under a sink. U-traps take up less horizontal space but may be more prone to clogging over time.