This sound deadening roller allows for even pressure of application, minimizes air bubbles and achieves the best adhesion.They are very heavy and have a quality bearing. Additionally, the ridges on the rolling surface give them great traction and makes it easy to see areas that have already been rolled. Having the smaller roller is also key for tight places such as center consol or pillar work.Due to the weight of the metal, you do not need have to use too much power to roll it. Five Sizes:40mm,20mm,12mm,6mm,4mm which can solve your problem well. Please refer to the picture for detailed specifications. These tools are needed if you want a professional look to your installation of sound reading or insulation material. Material:Wood Handle and Metal Connector.The metal wheel gives the tool some heft thus it’s easier to create tight seals all around.One can install the insulation material in your automobile without these tools. It is useful for sound deadening mat ,audio Noise Insulation and dampening Sound deadening roller is compact,easy to carry and conveniently for car sound deadening mat Auto Noise Sound Deadener makes the sound insulation pad more effectively installed on the surface of the car,it also can make tyre and tube patches adhere fully during repairs