Instead of manually adding the snippet of code to the head of your page, Google Tag Manager module by BSSCommerce provides a simple way to easily have the code added correctly on your site and enable/disable Google Tag Manager whenever you wish. The module also supports e-commerce data (including transaction data: id, affiliation, revenue, shipping, tax and Item Data: id, name, price, quantity) when you want to send to Google analytics for analyzing information of orders in more details.