Comet RS-840 mobile antenna adjustable lip mounts offer heavy-duty security for your 80 in. antenna. Strongest of the Comet mounts, these RS-840s feature a support tab that crosses over the gap between the trunk/door edge for additional strength! A through-bolt tightens and clamps the mounts in position after adjusting to vertical to prevent slippage or movement. The mounts are outfitted with soft rubber gaskets to protect your vehicle's paint, have a sizeable footprint, and are secured with four large set screws.