Ram Mounts RAM-PA5409. This 9" Long Rigid Aluminum 1/4" diameter Pipe is powder coated and has a 1/4" NPT Male thread at either end. These arms are used for many of the Lap Top Tray Mounting Systems. They are rigid pipes that can securely hold many different types of weights. Please note that these NPT threads are significantly different in size from standard measurements and are only compatible with other NPT parts of the same size.