Product#: TG-2190 Availability: This item normally ships within 1 - 2 business days. Description: Similar to 2180, except that ribs are molded into the glass so that they cannot pop off as they might with standard watch glasses. Permits reflux of digestate and escape of excess vapor. Eliminates risk of contamination from dropped hooks or props. Meets EPA requirements for methods 3005, 3010 and 3020.