RAM Mounts RAM-201U 双插座中臂支架，兼容1.5英寸球头组件，适用于车载导航和户外设备安装

•Most of the time they use a different kind of rubber for the balls that have a metal base than they do for the composite ones•They are also a slightly different size• The metal ones use a natural rubber that compresses and deforms when it is clamped & this locks them in place• The composite based balls use a rubber that is formed at a lower temperature so that the composite doesn’t melt. This rubber is much harder ( so for the most part it doesn’t compress and deform to lock it in place) It is stickier and relies on friction•If you find the ball is moving in the arm even when it’s very tight then You might want to change to aluminium or composite depending which one you are useing•It’s been my experience that sometimes you should use the composite arms with the composite balls and use the aluminium arms with the metal based balls for the most secure connection• The pics show how the metal base balls compress when tightened• sometimes no matter how hard I tighten the aluminium arm the composite based ball moves• sometimes when I use a composite arm or clamp the metal based ball would not compress enough and it would moveHOPE THIS WAS HELPFULOn my kayak.It does exactly what it says it does . Better than anything on the market.Ram mounts have always made great products. Use them on my boat.The arm is very strong and sturdy.Pay attention that it is really long, so think twice before you decide whether to buy this one or the other sizes (medium or small).The only reason I’m getting the C size is because the B size which is the 1” ball doesn’t last long when I use it with a longer arm double socket. After a year or so of use, the ball component gets crushed looking like a deflated ball. I’ve used it for my iPad and now iPhone as soon as I buy the C size X-grip.The downfall of this super expensive item is that they are cheap enough to include only one spring. The casing calls for 2.Found an amazon item B07MB8V6G5 that works as extra springs. So, the included spring I put on the bolt and the 2 springs from B07MB8V6G5 item on the sides, there where springs go. Very happy with the result.I lost my double socket in the lake when I was taking my fish finder off my boat. Purchased another one because it’s a great way to adjust my electronics so I can see them from anywhere on the boat. It’s tightens up and holds agains the chop on the water and at speeds when traveling.Como todo lo fabricado por RAM, muy bien resuelto y de primera calidad. Junto con dos soportes de bola de 1,5" lo uso para sujetar una carcasa estanca para un iPad 2. El cojunto es pesado, pero las bolas aguantan en su sitio sin aflojarse y soporta perfectamente los golpes y vibraciones propias de la navegaciónDoes exactly what a Ram mount does.Sturdy,heavy and built to last.Support pour sonar très bon produitJunto con las demás piezas,es el mejor sistema de sujección que he tenido.Good- expensive but had no other option.