1Heat oven to 250°F. On large cookie sheet, place pretzels in single layer. Place caramel piece on center of each pretzel. Bake 6 to 8 minutes or until caramels have softened. Remove from oven. Press pecan half into each caramel piece. Place close together on sheet of waxed paper.
2In separate 1-quart resealable freezer plastic bags, place chocolate chips and vanilla chips; seal bags. Microwave each on High 35 to 50 seconds, squeezing chips in bag every 15 seconds, until chips are melted and smooth.
3Cut small tip from bottom corner of each bag. Drizzle melted chocolate over pretzels. Carefully drizzle melted vanilla chips over chocolate. (If careful when drizzling, there is no need to let the chocolate set before drizzling the vanilla chips.) Refrigerate about 20 minutes or until chocolate is set.