A hint the marmon (sp) clamps can and will pop open under unknown load conditions, been there done it. So when I add a mast as it clears the top of the elevator I place a stainless hose clamp on it. I NEED ONE PREFER TWO MAST UNITS AS ONLY 3 OF 10 MADE IT FROM CA IN THE MOVE. Hank KN6DI/5 McKinney TX