diff --git a/Customize-Font-Awesome.md b/Customize-Font-Awesome.md
index ea1f1ae..c9c34a0 100644
--- a/Customize-Font-Awesome.md
+++ b/Customize-Font-Awesome.md
@@ -23,13 +23,15 @@ In the following examples, I'm going to use add to Font Awesome 5 the `fa-list`
 
 #### With local/CDN `fontawesome/all.js`
 
+⚠️ Pseudoelements will not work with this method!
+
 JavaScript:
 ```js
 // replace 1568, 1568 with your SVG viewbox
 // e001 is the unicode point which represents this custom icon. Increment this value for other icons
 // replace 'M256...' with your single-path SVG
 var faListOldStyle = {
-  prefix: 'fas',
+  prefix: 'fac',
   iconName: 'list-old-style',
   icon: [1568, 1568, [], 'e001', 'M256 1312v192q0 13-9.5 22.5t-22.5 9.5h-192q-13 0-22.5-9.5t-9.5-22.5v-192q0-13 9.5-22.5t22.5-9.5h192q13 0 22.5 9.5t9.5 22.5zm0-384v192q0 13-9.5 22.5t-22.5 9.5h-192q-13 0-22.5-9.5t-9.5-22.5v-192q0-13 9.5-22.5t22.5-9.5h192q13 0 22.5 9.5t9.5 22.5zm0-384v192q0 13-9.5 22.5t-22.5 9.5h-192q-13 0-22.5-9.5t-9.5-22.5v-192q0-13 9.5-22.5t22.5-9.5h192q13 0 22.5 9.5t9.5 22.5zm1536 768v192q0 13-9.5 22.5t-22.5 9.5h-1344q-13 0-22.5-9.5t-9.5-22.5v-192q0-13 9.5-22.5t22.5-9.5h1344q13 0 22.5 9.5t9.5 22.5zm-1536-1152v192q0 13-9.5 22.5t-22.5 9.5h-192q-13 0-22.5-9.5t-9.5-22.5v-192q0-13 9.5-22.5t22.5-9.5h192q13 0 22.5 9.5t9.5 22.5zm1536 768v192q0 13-9.5 22.5t-22.5 9.5h-1344q-13 0-22.5-9.5t-9.5-22.5v-192q0-13 9.5-22.5t22.5-9.5h1344q13 0 22.5 9.5t9.5 22.5zm0-384v192q0 13-9.5 22.5t-22.5 9.5h-1344q-13 0-22.5-9.5t-9.5-22.5v-192q0-13 9.5-22.5t22.5-9.5h1344q13 0 22.5 9.5t9.5 22.5zm0-384v192q0 13-9.5 22.5t-22.5 9.5h-1344q-13 0-22.5-9.5t-9.5-22.5v-192q0-13 9.5-22.5t22.5-9.5h1344q13 0 22.5 9.5t9.5 22.5z']
 }
@@ -41,7 +43,7 @@ FontAwesome.library.add(
 
 HTML:
 ```html
-<span class="fas fa-list-old-style"></span>
+<span class="fac fa-list-old-style"></span>
 ```
 
 Example: https://jsfiddle.net/tagliala/we7gtcvk/1/