Choose foam which offers a balanced absorption of mid and superior frequencies to control reflections and reverberations. Armaflex® Rail foam comes in two grades; either regular SD or SD-C which is the standard SD materials but by using a silver metallic seem coating. The above mentioned specifications are those in https://sound-absorbing-rubber-fo85163.ageeksblog.com/30293766/air-conditioning-pipe-insulation-an-overview