Crushproof® 3" aluminum door port for use on 1" thick doors.
"CRUSHPROOF®, CT® (and the CT logo), FLARE-LOK®, CUSTOMFLEX®, UNIHOSE®, SAFETY PORT®, EXHAUST-AWAY® and CYCLOVAC® are registered trademarks of Crushproof Tubing Co. in the United States and other countries and are being used with permission."