MEC Brass Prep Rotary Tumbler 131. Just pour your clean brass and media into the middle hopper close and rotate the handle to separate brass from media. Specifications for MEC Brass Prep Rotary Tumbler 1311096: Manufacturer: MEC Fabric/Material: Brass Package Contents: MEC Brass Prep Rotary Tumbler 1311096 The MEC Brass Prep Rotary Tumbler 1311096 is a quality addition to the MEC lineup. For more great deals on Case Tumblers by MEC please browse our Mec Reloading Equipment page. MEC Brass Prep Rotary Tumbler 1311096