- AED 57.65When it comes to venting and porting, Drum Os gives you plenty of options. Its 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 colors, including Black, White, Chrome & Brass, in addition, there are 4 new Chrome colors Red, Blue, Green & Purple. <br><br> DRUM O's has taken personalizing your bass drum or any drum head and made it easier than ever. Even a CAVEMAN can do it. Different sizes and shapes, different colors, they look great, easy to install and makes the drum sound better than ever. <br><br> Drum-O's makes personalizing your bass drum so easy anyone can do it! They have many different sizes and shapes, but just one EASY setup and then placement is all you need to quickly change up your bass drum to reflect your individual style. Take your drums up a beat with Drum-Os . . . where quality always comes standard.