We are Particle counter,Formaldehyde detector,gas detector manufacturers in China.
Particle counter video:http://youtu.be/fqXYDKkdp0A
Formaldehyde detector video:http://youtu.be/SSlVjB6xoXI
If you interested pls contact me for more detail,thanks.
Best regards
Katrina WhatsApp: +86 13533537019
Guangzhou LanJia environmental protection technology Co., LTD