I have been using a CB3000 for sometime now which was not secure without using the KSD security ring it was not really comfortable for extended wear the cuff hinge was a problem . The CB6000 is so much better, the person who designed it must have worn the CB3000 . CB6000 fits like a glove on your shaft and the enhanced end allows a bit of movement but only until the glans expands to fill it ! It looks really good then for your keyholder. The cuff ring is a better more secure size . I dont think you will escape from this one and the build quality is improved also