The CO2 MANIA® external cylindrical crystal glass bubble counter for aquarium CO2 has been designed and built with the best materials in Asia and are all tested* in Italy. The machine-blown technical crystal glass structure and its tapered shape finely drilled to art make (02-CN-ExtBubbletap) very elegant and easy to read, the precision of laser cutting allows extremely precise bubble counting, avoiding waste of gas. The circular bubble counter (02-CN-ExtBubbletap) is distributed by CO2 MANIA® and is recommended for Co2 type gases. _Technical features_ - Recommended minimum inlet pressure 3bar/43psi - Technical crystal glass bubble counter (length 11.1cm X width 1.6cm) - Direct coupling inlet connection for 4/6/8mm PVC pipes - Product tested* in Italy - We recommend applying it to the glass of your aquarium with suction cups. (not included)