This black plastic mouthpiece is oval shaped on the mouthpiece end and round where it enters the pipe. It is a replacement for our hardwood PHW** models and rainbow wood PRW** models. They are sized slightly larger than the original mouthpieces because they are generally used to replace one where the wood has worn out. In some cases it may be necessary to bore out the pipe depending on the level of ware. The only exception are the models that use our compact tobacco bats as their mouthpieces.