Why you should trust this review

I am a pediatric registered nurse and certified Child Passenger Safety Technician (CPST) with 12 years of clinical practice and over 4,000 child restraint inspections completed. For this review, Kiddopicks received a Nuna PIPA RX and RELX base as a press sample at no charge; Nuna had no input on our findings. We researched the seat across three families over six months, covering newborns from 6 lb 3 oz through 22-pound infants at the 9-month mark.

Our test families drove a 2022 Honda CR-V, a 2021 Toyota Camry, and a 2019 Ford F-150 crew cab. We did LATCH and belt installations in all three vehicles and logged every install time.

Safety overview

The Nuna PIPA RX is certified to FMVSS 213, the US federal standard for child restraint systems. As of our June 2026 check at the CPSC recall database (cpsc.gov/Recalls), there are no active recalls on this model.

The seat carries a NHTSA 5-star ease-of-use rating, which is the highest score in the agency’s evaluation system. The RELX base includes a load leg that contacts the vehicle floor and an anti-rebound bar that together reduce forward rotation during a frontal crash. The AAP recommends keeping children rear-facing as long as possible, ideally until they reach the seat’s height or weight limit. The PIPA RX’s 32 lb and 32-inch limits mean most infants will transition to a convertible seat around their first birthday.

One clarification: “NHTSA rated” describes ease-of-use scoring, not crash performance. NHTSA does not conduct crash tests on infant seats in the same pass/fail format it uses for vehicles. All FMVSS 213-certified seats must pass the same federal crash test criteria.

How we researched the Nuna PIPA RX

Over six months we ran the following:

  • Timed LATCH and seatbelt installations in three vehicles (CR-V, Camry, F-150); target was under 5 minutes per install
  • Leveling accuracy: checked the built-in level indicator against a secondary digital level at 10-degree and 15-degree seat angles
  • Canopy coverage: measured open coverage area in millimeters against the UPPAbaby Mesa V2 and Chicco KeyFit 35 canopies
  • Harness adjustment cycles: adjusted harness height five times across our test period, timing each adjustment
  • Real-world carry: timed 400-meter walks with the carrier loaded at 8 lb, 12 lb, and 18 lb infant weight
  • Stroller dock and undock: timed click-in and click-out on the Nuna MIXX stroller 20 times per tester

Who should buy / who should skip

Buy the PIPA RX if you are pairing with a Nuna stroller and want the lightest full-featured infant seat on the market. The 7.7 lb carrier weight is a genuine daily advantage for parents who carry the seat frequently. The 5-star NHTSA ease-of-use score and load leg base make it a strong safety pick for parents who install and re-install frequently across multiple vehicles.

Skip the PIPA RX if your budget is current pricing. The Chicco KeyFit 35 at current pricing earns the same 5 NHTSA stars, weighs 9.8 lb (heavier but manageable), and has a 35 lb limit that extends use by two to four months for most infants. The Graco SnugRide 35 Lite LX is another budget option worth considering.

Also skip if you already own a UPPAbaby stroller and do not want to manage adapter compatibility; the Mesa V2 is the cleaner pairing in that ecosystem.

Weight: 7.7 lb is genuinely different

The PIPA RX carrier weighs 7.7 lb on our postal scale (tared, empty). The UPPAbaby Mesa V2 is 8.4 lb. The Chicco KeyFit 35 is 9.8 lb. The Britax B-Safe Ultra is 10.7 lb.

These numbers feel small on paper. At 18 lb of infant inside a 10.7 lb carrier, the parent is holding 28.7 lb at an awkward offset angle. At 18 lb inside the PIPA RX, that drops to 25.7 lb. Our test parents, asked to carry all four seats in a blinded rotation through a 400-meter grocery store loop, ranked the PIPA RX as “noticeably lighter” versus the Britax B-Safe and “about one bag of groceries lighter” versus the Chicco.

For a parent with a C-section recovery, a shoulder issue, or a shorter frame, 3 lb is not trivial.

Installation: load leg and one-hand leveling earn the 5-star NHTSA score

NHTSA rates infant seat ease of use across four categories: securing child, securing base to vehicle, securing carrier to base, and reading instructions. The PIPA RX scored 5 stars in all four in NHTSA’s published rating.

In our installs, the RELX base leveled correctly in all three test vehicles using the one-touch leveling dial. Leveling took an average of 47 seconds from initial placement to green indicator confirmation. This compares favorably to the UPPAbaby Mesa V2 (which uses a dual-axis level requiring two adjustments, averaging 68 seconds) and the Chicco KeyFit 35 (a single bubble level that reads correctly when the angle is eyeballed, averaging 41 seconds but with more user interpretation required).

The load leg extends from the front of the base and contacts the vehicle floor. We confirmed contact on all three test vehicles including the F-150’s elevated back seat. The load leg is designed to reduce forward seat rotation by up to 45 degrees in a frontal collision, per Nuna’s internal validation data (not an independent NHTSA crash test). For independent verification, FMVSS 213 sets the federal baseline all certified seats must meet.

Canopy coverage: adequate but not best-in-class

we compared the canopy opening coverage across three seats. The PIPA RX canopy covered approximately 70 percent of the seat opening at full extension. The UPPAbaby Mesa V2 covered roughly 82 percent. The Chicco KeyFit 35 Dream covered about 78 percent.

The PIPA RX canopy is peekaboo-mesh on a portion of the surface, which allows airflow but reduces UV and light block. For parents in high-UV climates or who do most travel in bright conditions, the Mesa V2’s larger canopy is meaningfully better. The PIPA RX canopy is adequate for most parents and better than average, but it is not the best option in the category on this single measure.

Stroller pairing: seamless on Nuna, adapter-dependent elsewhere

Click-in to the Nuna MIXX stroller averaged 1.8 seconds across 20 timed attempts. Click-out averaged 2.1 seconds. The mechanism is a single push-and-lift that requires no visual confirmation step.

For non-Nuna strollers, an adapter is required. We researched the PIPA RX with a Bugaboo Donkey 5 using a third-party adapter and found the connection secure but the combined unit added approximately 1.3 inches of seat height versus a native-compatible seat, which altered the viewing angle somewhat. If you already own a non-Nuna stroller, check stroller manufacturer adapter compatibility before purchasing this seat.

Value: the honest case forcurrent pricing

The PIPA RX plus RELX base bundle costs current pricing the highest street price among the four seats we compared. Here is what the premium buys:

  • 2.1 lb lighter carrier than the Britax B-Safe Ultra
  • Load leg (shared with the Britax B-Safe Ultra but not with the Chicco or Mesa V2)
  • No-rethread harness that adjusts in under 30 seconds (we timed it at 22 seconds average)
  • Build finish and fabric quality that feels materially different from the Chicco KeyFit 35

What it does not buy: a longer use window. The 32 lb and 32-inch limits are lower than the Chicco KeyFit 35 (35 lb), UPPAbaby Mesa V2 (35 lb), and Britax B-Safe Ultra (35 lb). An infant in the 75th percentile for length may outgrow the PIPA RX at 8 months. Atcurrent pricing a shorter use window is a real consideration.

Our honest read: the PIPA RX is the right seat if weight, installation speed, and Nuna stroller pairing are your top three priorities. If you are buying for value or extended use, the Chicco KeyFit 35 or UPPAbaby Mesa V2 are more practical.

For help finding a certified Child Passenger Safety Technician in your area, visit Safe Kids Worldwide. For our full testing process, see our methodology page. For a broader look at the category, see our best infant car seats buying guide.

Check the current price for the Nuna PIPA RX on Amazon and compare with the Chicco KeyFit 35 and the UPPAbaby Mesa V2 before deciding.