An extension for a catheter assembly may include a distal end and a proximal end. The distal end may include one or more cantilever arms and an insertion feature spaced apart from the cantilever arms. The insertion feature may be configured to insert into a lumen of a catheter adapter to provide a fluid connection between the catheter adapter and the extension. The one or more cantilever arms may be configured to engage in a snap-fit with the catheter adapter. The proximal end of the extension may include a female luer fitting.