I have the Street F135/R14. What does the F and R mean? Donna Post January 19, 2017 18:54 Updated Kryptonite uses the following naming structure: F-14 F=Front 14=Lumen R-3 R=Rear 3=Lumen Related articles How do I know if the light will fit my bicycle? How do I charge my light? What is COB? How long will a single charge last? What does the X mean on the light? Comments 0 comments Article is closed for comments.