Caplugs RPO-M Series Threaded Plugs for ISO Metric Ports are designed to provide a positive seal for straight-threaded ISO ports and bosses on fluid power components. The integral O-ring-type bead seals in the bevel of the port to prevent fluid leakage or entrance of contaminants. These plugs have two unique design factors that make them easy to install and therefore remove. The first is up top, on the wider end. There is a series of ribs spaced throughout the circumference of the top part making for an easier grip when putting in or taking out. Below the head, there are two ribs on the inside that create a tight seal once pushed in, as they stick our and to the sides of whatever port they're placed in. There are different sizes of threaded plugs in the RPO-M Series to suit your various needs. This particular plug is made to plug a metric thread size of 18 x 1.5. It has the following dimensions: Thread Height 0.41" x Total Height 0.85" x Width 0.97". When tightening a Caplugs Plug for Metric Threaded Ports, you have an option of tools to use thanks to the slotted 12-point head. This is able to be tightened by using a screwdriver, socket or a wrench. This makes for a universal, accessible way to properly tighten these plugs. Caplugs prides itself on its extensive line of premium products that are suitable for a plethora of industries, from aviation to medical, general manufacturing and everything in-between. At Caplugs, we provide the broadest range of solutions and the highest quality parts right when you need them. Our teams work diligently to ensure consistent results, with more engineers on staff, processes for creative solutions and molding experts for reliable quality.