The cage portion is separated into two halves. His cock goes through the hole in the bottom portion and the top portion is fit over it. The shape of the two halves mean you have just enough space to sqeeeeze everything in while flaccid.
The cage is 4" in total length. The spacers leave room for 1/2", 3/4", or 1" diameter for the cock and balls depending on how you space it.
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