Need a replacement for your beug? Look no further! These silicone grommets have a 10mm inner to suit a standard stem (which is what our Chongz acrylics use), and 28mm outer. They are used with bongs that would normally use a bonza sized stem (15-18mm). They are 10mm thick ensuring that you have a slip free attachment to hold your stem and cone piece in place. These grommets are strong, durable and easy to pull apart and clean.