The 51M30-01-1-09N is a single-deck rotary switch from Grayhill's Series 51 designed for compact panel-mount applications requiring precise position selection. It features a 0.5" diameter with a 30° angle of throw, 1 pole, 9 positions per pole, and non-shorting contacts rated for 200 mA operation. The switch includes a 1/4"-28 UNF-2A threaded terminal for solder lug termination, with optional complete seal for PC board assembly and cleaning, and positive shaft grounding for EMI/RFI shielding. The behind-panel depth is 0.698", making it suitable for space-constrained control panels, instrumentation, and switching applications where reliable multi-position selection is required.