If can not fit(too samll), please put on the hot water then can fit, becuase it is resin.<br><br>Numbers of air vents: <br>The whole set contains:<br><br>1. 4 different size of rings.<br>2. 1 Cage<br>3. 1 Magic Locker (high quality) with 2 keys.<br><br>Size:<br><br>4 different Rings: 82mm/97mm/102mm/110mm<br><br>Nano: inside length is about 82mm (3.23inch)<br><br>Small: inside length is about 97mm(3.82inch)<br><br>Standard: inside length is about 102mm (4.02inch)<br><br>Maxi: inside length is about 110mm (4.33inch)<br><br>Inner Size:<br><br>Nano & Small (1.3inches)<br>Standard & Maxi (1.4inches)