Great product, comfortable to wear, well designed with quality materials. The gel cushions well for all day walking. The extra 1" (2 cm) adapters (adds more height) are design with mating keys the mate to the larger piece attaching them securely without movement, see the pictures on their site. These additional parts make a great feature when you are wearing boots or anything that can hide your heel from showing above the rear edge of the shoe. I do recommend them.
SUPER fast shipping. Item is great, ordered the 5cm however only needed to use the 3cm height. The 5cm would have been too high and uncomfortable in my running shoe.