All the moving parts of trim are stainless steel which is wearability and anti-corrosive. For the steam cannot arrive to the valve seat hole by the water sealing that does not have steam losing and have highly effective energy saving. It can't be destroyed and staved because of the Inverted bucket. It can bear water hammer and have a long usage circle. It has air vent in the top of Inverted bucket. It has good performance to continuously vent air to lest Cold lag and aired up. It can't influence by the back pressure and working well in the high back pressure. It Works reliably, only has two movement parts (lever and Inverted bucket. ) so that cannot form hinder. The valve seat and disc are in the top of valve, the valve disc may cause the contamination passing in the on and pass. It has the good self- clean performance and no contamination.