Shopback have now transitioned their Amazon cashback rates to a tiered system. It also appears that the $50 capping has been removed.
The 12% cashback also stacks with the promo code FASHION10 - 10% off Your First Order of Fashion (Eligible Clothing, Shoes, Watches or Luggage).
All cashback rates subject to change.
Edit: See the new 8% Cashback On Sport, Toys, Baby Products, Home Improvements, Home + Other New Rates post for up to date table.
What would a smartwatch fall under - Watches or Consumer Electronics & Accessories ?