Ram Mount Universal D Size Ball Mount with Short Arm and Hi-Torq Wrench for 9"-12" Fishfinders and Chartplotters [RAM-D-115-C-KNOB9H]Universal D Size Ball Mount with Short Arm and Hi Torq Wrench for 9" 12" Fishfinders and Chartplotters The RAM D 115 C KNOB9H consists of a base with a 2. 25 diameter D size ball, a short arm, a Hi Torqwrench and a 6. 25 x 2 marine electronic plate with a D size ball for supporting larger devices. This marine electronic plate contains different combinations of pre drilled holes and is a direct fit for 9 12 fishfinder gimbal brackets. For cold weather