Yes they can be unlocked with special keys, but they are made to be worn at all times. We chose the platinum collar for her with a special agreement: If I'm paying $160 (Plus tax) for this, she has to be a true submissive. If I say something is an "Order" she has to do it. We can be standing in a room full of people and if I order her to offer blowjobs to all the guys, she has to do it.
We wanted the eternity collars because they look more like jewelry instead of some cheap dog collar, so they can be worn at any time of place and still fit in. Unless someone knows what they mean, they will think it is just a nice accessory. Also they can be worn in water with no worry of rust. Plus you can buy things to add on like a name tag, or ring for a leash. They also sell some for the wrists and ankles so that you can go full bondage with them. We're starting with just the collar and if it meets our fantasy ideas, we plan on getting her the full set as funds become available.