The Cole-Parmer dual-inlet bottle top dispensers feature a dual valve technology making it easy to rinse the instrument and refill a bottle without removing the dispenser. The dispensers offer four modes of operation: standard dispensing, purging, dilution/rinsing/second liquid dispensing, and bottle refilling. Borosilicate glass ball & seat valve assembly is 100% spring-free providing for many years of reliable operation with a wide range of harsh chemicals. 360° rotating base provides dispensing from any position