Here we have a very rarely seen Zenith reference A6621 referred to as the keyhole based on the design created by the stainless-steel plate covering over a portion of the crystal. This has been a battleground watch in terms of enthusiast who either love the design or loathe it. Personally, I think it is a style masterpiece which screams to the design of the late mid-century modern movement. It was significant to the brand in that production occurred to celebrate the centennial of the company in 1965. The bi-tone non- traditional art deco clean dividing lines reminds me of some of the great New York City prewar architecture which is currently being torn down for horrendous modern crap. The NSA bark and beads bracelet is super soft, comfortable, and incredibly well-made. The end links hug the case perfectly and complete an overall clean but complex style. The signed nearly hidden crown is easy to manipulate yet near non-noticeable to the eye. Inside of his 36 mm icon, is the Zenith caliber 2542 PC movement which is front loaded to the case.