diff --git a/static/index.html b/static/index.html
index 3be568c..0bce863 100644
--- a/static/index.html
+++ b/static/index.html
@@ -141,6 +141,7 @@
               <label>Colour<input type="color" v-model="drawColor" aria-label="Fibonacci colour"></label>
               <label>Width<select v-model.number="drawWidth" aria-label="Fibonacci width"><option v-for="width in 9" :value="width">{{ width }}px</option></select></label>
             </div>
+            <label class="check"><input type="checkbox" v-model="snap">Snap to highs/lows</label>
             <p class="hint">Drag from one swing to the other. Levels at 0, 23.6, 38.2, 50, 61.8, 78.6 and 100.</p>
           </div>
         </div>