B agile 3 and 4 click go receivers allow you to instantly turn your b agile 3 and 4 in to a travel system with full compatibility with all britax baby safe infant carriers and the britax hard carry cot on to the b agile 3 and 4guarantee2 year guarantee for manufacturing or material defects on all products for two years warranty begins on the date of purchase please retain receipt as proof of purchase and complete your warranty card if available