The CAT II Q retainer is meant to be used with a regular size (1-3/8") CAT outer cone to get started if you don't yet have enough skin to apply tension.  It can also be used to maintain the skin you have already restored.  The outside of the retainer is just like the CAT puller however, inside is a smooth bore and will not work with the collet as a puller. The retainer will not be compatible with any of the smaller (1") devices. As always, use caution with your device and DO NOT wear during sleeping hours as nocturnal erections while wearing a device could lead to injury.