... blowers are of better quality,performance and after-sale services.Less vibraion and lower noise. AIR Roots Blowerstwin-lobe ... : HT20013. Shell: HT20014. QT450 wall plate:HT20015. Accessories: inlet filter, outlet silencer, expansion joint, check valve, foundation bolts, pressure ... ; what’s more, we have obtained ISO9001 International Quality Certification.Our company possesses profound technical R & D ...