All MICRO SWITCH HDLS Series Heavy-Duty Limit Switch, Plug-in, Side Plunger - Standard, 1NC 1NO SPDT Snap Action, 0.5 in - 14NPT conduit. Sensing and Control offers the world's most advanced line of MICRO SWITCH heavy-duty limit switches. These switches include boss-and-socket head design for secure head-to-body retention, unique all-metal drive train for consistent operating characteristics even at high temperature (lasts longer without the need for frequent adjustment than drive trains with plastic parts,) self-lifting pressure plate terminals save wiring time, easily identified grounding terminal (inside) for compliance with OSHA and other regulatory agency standards, one piece flat gasket (seals better than gaskets that go around curves and corners, does not contact terminal pins to reduce chances of fluid migration,) front mounting and interchangeability of single- and double-pole switches, plug-in and non plug-in with one another and with other switch brands, tracking interchangeability of actuator levers for single- and double-pole switches, plug-in and non plug-in, twin shaft seals for an extra measure of protection, inner FC O-ring seal, outer Buna-N seal (all FC available,) FC shaft and diaphragm seals on side rotary switches, rugged corrosion-resistant zinc head and body are phosphate treated and epoxy finished, exclusive teller tab assures proper torque (when it cannot be moved the lever is tight enough to prevent slippage) and domestic and international conduit taps.