Cartwell replaces the default cart with a fast slide-out drawer, so shoppers stay on the page instead of leaving for a separate cart screen. A free-shipping bar shows how close customers are to a reward, with separate thresholds per country. Upsell rules suggest relevant products at the right moment, and gift rewards add a free item automatically when a cart qualifies. Style the drawer to match your theme with presets, fonts, and colors, and track how the cart and each offer perform.