1. Brewing airlock can be used for wine making, beer brewing, fermenting sauerkraut, that can satisfy your daily fermentation need. 2. Simple to the stopper onto the carboy, insert the beer airlock to the stopper, pour some water into airlock and cover the lid to complete all operations. 3. Brewing airlock makes easier for the fermentation caused it could effectively isolate the air to prevent oxidation and allow the whole fermentation process to be automatic fermentation and exhaust at normal temperature without manual control. Specification: Suitable for preserving, brewing, making wine, beer, fermenting sauerkraut, . 5 x No. 3 stopper (15x21x24mm) Colour: white Material: plastic + silicone Size: exhaust valve: 115x40mm, bottle stopper: 15x21x24mm Package Contents: 25 x exhaust valve 25 x No. 3 perforated corks Note: Before use, please boil and disinfect the airlock with boiling water. Wash with water after use. Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.