This is Nina Zhang from Grand Index Solution Enterprise Limited, Our company is a professional distributer which specilize offer Gem instrument and all kinds of optical instruments. We need vacuum pumps: Electric Motor Power :1/4HP; Flow rate around 55 liters/minute; maximum vacuum :650 mmHg(85.5kPa); Rotor speed:2.800 rpm; nosie level :around 65 dB; weight :5.9 kg; dimensoes: 16*30.5*20 cm(L*P*A); Voltagem :220 Volts,50/60 Hz; Oil free operation; If your products are just meet the requirements, please contact us.