Create your own sound hole for microphone placement with these easy to use templates. The Remo 5 7 9 Inch Dynamo Holes are easy to apply and allow you to add a bass drum head port for a dry sound. These dynamo rings allow for repeatable microphone placement without the fear of ripping the exposed edge of the microphone hole. The templates feature an adhesive backing making them incredibly easy to apply and position wherever you require them. These sound hole templates are designed to match your bass drum and are suitable for any black drum head.