conditional - Shopify Custom Text box according to product collection -

im trying conditional if product in collection "personal" show text box. have in product.liquid page does't seem working.

   {% if collection.title == 'personal' %}             <div>                                            <p><input type="text" id="letter" placeholder="enter 6 letters" name="properties[letter]" /></p>             </div>    {% endif %} 

try this:

{% collection in product.collections %}   {% if collection.handle == 'personal' %}     <div>                                    <p><input type="text" id="letter" placeholder="enter 6 letters" name="properties[letter]" /></p>     </div>   {% endif %} {% endfor %} 

see shopify docs product.collections.