A through hole usually refers to a hole on a printed circuit board, which is used for fixed installation of connectors or interconnection between layers. A board characterized by such a hole is called a through hole printed circuit board.
Cement additive is a chemical additive to improve the grinding effect and performance of cement. The main material of the additive is fluorine gypsum, it come from the chemical reaction from fluorite and sulfuric acid.
The material is high cleanliness and has no pollution to the filtered media. The strength of the skeleton is high, which ensures the filtration area and service life of the filter layer.
Brown Switch Gaming Keyboard which is designed with 104 keys has the key switches of high quality. It offers over 20 million keystrokes’ life span and it is user replaceable.