Replacement Full Tilt tongues in flex 10/120. These tongues are compatible with evolution shells only and come as a pair. If you are unsure of which Full Tilt shell you have then count the screws on the bottom of the boot: evolution (8 screws), Original (2 screws), Influence (4 screws), Soul (9 screws), Growth Spurt (6 screws).To ensure your tongue fits correctly use the below size guide:SML 22.0-25.5 shellMeD 26.0-27.5 shellLRG 28.0-29.5 shellXLG 30.0-31.5 shell