①pressure up to 6000psig for stainless steel body
②temperature for PTFE packing from -54octo 232oc . temperature for grafoil packing from -54oc to 649oc
③packing below stem thread isolates the thread lubricant from the media
④PTFE ring in the gland protects stem thread from outside
    comination
⑤ color coded functional handles
⑥ non-rotating stem tips