Griffin Technology has debuted its new Slap wristwatch case for the sixth-generation iPod nano. Unlike other wristwatch cases for the new nano, Slap uses a flexible, spring-steel band wrapped in silicone to self-adjust to the user’s wrist, and also features a thick frame of silicone to protect the nano, push-through coverage for the volume and sleep/wake buttons, and open access to the headphone port and screen. Griffin’s Slap wristwatch…