Suitable for All NMO Mounts Antenna, Used to protect your antenna mount from rain and dust when antenna is not attached; The 304 stainless steel dust cap protects the NMO mount more tightly than plastic caps. Prevents water and accumulate dirt; O-ring seal on the inside of the cap, No need to worry about rain and dust; Keep the inside of the cap dry and tidy each time you remove it; Don't worry about any problems, we have carefully checked each product, Any questions, please feel free to contact us, will reply within 24 hours; This is a dust and rain cap made exclusively for NMO antenna, The threads are smooth and the seal is excellent, Stainless steel always lives longer than plastic, As you can imagine, when you have to wash your car or paint the roof and you need to protect the antenna mounts, this is definitely your best choice.