Bundler gives you the ability to customise the call to action button appearance on both Quantity breaks and Bundle offers.

1. For Quantity breaks #

For that go to Bundler -> Settings -> Quantity breaks -> Add to cart button:

From there you can change the background color, the border color, the text color and change the add to cart text.

2. For bundle offers #

For that go to Bundler -> Settings -> Bundles -> Button:

Here you can customise the button text and color.