Nuna's best-selling collection of infant car seats includes five models: the Nuna PIPA, PIPA RX, PIPA Lite, PIPA Lite R and PIPA Lite LX.

Choosing a Nuna PIPA model involves choosing both a seat and a base. 

As of 2020, Nuna offers two types of bases: the PIPA base (as seen on the PIPA, PIPA Lite and PIPA Lite LX) and the RELX base (used on the PIPA RX and PIPA Lite R). The RELX base solves common installation problems while offering four recline positions to add comfort for your baby.

The three PIPA Lite models are the lightest car seats in the world, weighing under 6 pounds, while the PIPA and PIPA RX models are also light at 8 pounds. Weight differences aside, the major difference between the two types of seats is that the PIPA versions can be installed with only a seatbelt for travel, while the PIPA Lite versions require a base at all times.

See this post for an in-depth look at the differences between Nuna PIPA models.

All Nuna infant car seats can be used with strollers from Nuna and several other brands. See the strollers compatible with the Nuna PIPA series here.