Since this your first one get one with multiple adjustments (spacers and rings) the full enchilada. You don't want to be going back to get the missing pieces and parts at additional expense. Get a cheap one and be prepared to endure sharp ill fitting edges on some of the parts. Also note that cheap CBs are a fantasy best left at that a fantasy. The chrome metal ones are much better than plastic as the edges are most apt to be rounded and metal can be made sanitary in hot water without melting and losing shape. On the high end of chastity devices is the belted ones which encircle the waist with a crotch strap (with optional plugging and vibration devices) and a semi flat front shield for better discrete wearing. I have found of interest is the non-belted models with a interior urethral tube inside the penis tube that defines chastity in another way. As with most all CBs the wearer
is committed to sit while urinating if not it is suggested to be wearing diapers as there is little control of the spray pattern - the women's ones are not immune from this. And in closing make serious plans on who is the KEY HOLDER and where the keys are to be kept and what terms an emergency entails and amusingly the Fire EMT Police Rescue
people have seen it all - try and make their job easier - you don't want the jaws-of-life getting to close to the flesh ! Oh and have a nice day !