# Infant car seat bases and carrier or belt compatibility Which infant car seat bases are limited to certain car seats, or to certain vehicle belts or vehicles? Chicco KeyFit Infant Car Seat Base: Only Chicco KeyFit/KeyFit 30 carriers are to be used with KeyFit/KeyFit 30 bases\. The base can be installed with LATCH and SuperCinch or with the vehicle seat belt using integrated lock\-offs\. The base is large and may be a tight fit in smaller vehicles\. PEG Primo Viaggio Extra Base: The base fits the Primo Viaggio 4\-35 infant car seat\. The base is compact enough to fit in smaller vehicles, similar to the Chicco KeyFit based on the reviewer's measurements\. Britax Aspen Infant Car Seat Base \(with ClickTight\): The Aspen base works with Britax Willow, Willow S, Willow SC and Cypress infant car seats\. Britax Alpine: The store page lists compatibility with Willow, Willow S, Willow SC, and Cypress infant car seats\. ClickTight installation works with either the vehicle seat belt or lower connectors\. ### 1. [Chicco KeyFit Infant Car Seat Base](/products/ucp/strolleria-com/8064564822090) (sold by strolleria\.com) Only Chicco KeyFit/KeyFit 30 carriers are to be used with KeyFit/KeyFit 30 bases\. - Carrier compatibility: Only Chicco KeyFit/KeyFit 30 carriers are to be used with KeyFit/KeyFit 30 bases\. (manual) - Belt or LATCH install: The base can be installed with LATCH and SuperCinch or with the vehicle seat belt using integrated lock\-offs\. (listing) - Vehicle fit: The base is large and may be a tight fit in smaller vehicles\. (review) ### 2. [PEG Primo Viaggio Extra Base](/products/ucp/strolleria-com/5736681345) (sold by strolleria\.com) The base fits the Primo Viaggio 4\-35 infant car seat\. - Carrier compatibility: The base fits the Primo Viaggio 4\-35 infant car seat\. (listing) - Belt or LATCH install: - - Vehicle fit: The base is compact enough to fit in smaller vehicles, similar to the Chicco KeyFit based on the reviewer's measurements\. (review) ### 3. [Britax Aspen Infant Car Seat Base \(with ClickTight\)](/products/ucp/strolleria-com/8063439568970) (sold by strolleria\.com) The Aspen base works with Britax Willow, Willow S, Willow SC and Cypress infant car seats\. - Carrier compatibility: The Aspen base works with Britax Willow, Willow S, Willow SC and Cypress infant car seats\. (listing) - Belt or LATCH install: - - Vehicle fit: - ### 4. [Britax Alpine](/products/ucp/strolleria-com/7810848391242) (sold by strolleria\.com) The store page lists compatibility with Willow, Willow S, Willow SC, and Cypress infant car seats\. - Carrier compatibility: The store page lists compatibility with Willow, Willow S, Willow SC, and Cypress infant car seats\. (guide) - Belt or LATCH install: ClickTight installation works with either the vehicle seat belt or lower connectors\. (guide) - Vehicle fit: - Every value in the table is a fact RoboTrunk checked, linked to the page it came from\. A dash means no checked fact fills that cell\. Prices and stock change, so this page prints neither: each product name links to its RoboTrunk page, which shows them live\. Written 2026-11-01T07:32:05.179Z. This page is published by RoboTrunk, a store built for shopping agents. The store named on this page sells the product and ships it. RoboTrunk is not the seller and never holds the money. Buying works in one path. RoboTrunk's tools prepare a checkout at that store, then hand back a short-lived link. The person approves the total; once RoboTrunk has checked the store's total against it, the person is given the checkout link to tap in their own browser, or, if the person prefers and gives permission, their agent may open the link and finish there, and payment always happens on the store's own checkout page. RoboTrunk never takes the payment or sees a card. Where the rest of this site is: - /agent/story.md is what RoboTrunk is and how it works, in full. - /agent/tools.json is every tool, its arguments and its answers. - /agent/merchants is every store you can buy from through RoboTrunk. - /products/ucp is every store's indexed products. - /products/search is one search across every store, in plain words. - [What RoboTrunk is](/agent/story.md) - [Every tool, in your browser through WebMCP](/agent) - [The tools and how to call them](/agent/tools.json) - [The stores you can buy from](/agent/merchants) - [Every store's products](/products/ucp) - [Search every store at once](/products/search)