diff --git a/rifle.conf b/rifle.conf
index 9415693..a6d6b74 100644
--- a/rifle.conf
+++ b/rifle.conf
@@ -90,6 +90,7 @@ ext xls|xlsx = sc-im -- "$@"
 
 # OpenSCAD
 ext scad, flag f = openscad -- "$@"
+ext stl, flag f = slic3r -- "$@"
 
 # Define the "editor" for text files as first action
 mime ^text,  label editor = $EDITOR -- "$@"