Simple, Easy to use and a great solution to venting and porting your resonant bass drum head. Bass Drum O’s make it easy for mic placement whilst also preventing splitting. They look great as well and come in a range of colours and sizes. this ring sits around the hole you put in your drum and protects the edging from taking any microphone damage on stage and in the studio. Here’s what Drum O’s say about their Drum O’s range When it comes to venting and porting, Drum Os gives you plenty of options. It's easy to get creative with Drum Os because there are endless design possibilities. Drum O’s now come in 2, 4 & 6-inch diameters! Also each size is available in 8 great colours, including Black, White, Chrome