RAM® 4インチ角柱クラッチベース（1/2インチNPTポスト付き）

Finally, a mount that actually stays tight on a square post without any wobble. The flat clamp base grabs evenly, and the 1/2" NPT post is exactly the right size for my marine antenna. Really solid feel when you ratchet it down.

The ratchet mechanism clicks into place with a satisfying solidity, and the 1/2" NPT post threaded onto my existing gear without any wobble. I've got it clamped to a 4" square post on the boat, and after a weekend of chop, it hasn't budged a millimeter.

I was pleasantly surprised by how sturdy the ratchet arm feels when tightening it onto the square post. The flat clamping base holds firm without any wobble, which is exactly what I needed for my setup.