use of breather in transformer

{"cid":"91200371","title":"Light Weight 3kg Silica Gel Air Dehydrating Breather For Transformer Moisture Absorber","imgUrl":"https:\/\/img.ismap.com\/nimg\/0b\/4f\/b3c96e486e2d1b0336ed6582c3b5-200x200-1.jpg","attrs":{"Price":"negotiate","Brand Name":"Hebei Maier","Model Number":"XS3-3kg","Minimum Order Quantity":"1 piece","Delivery Time":"3-10 work days","Certification":"CE","Place of Origin":"Hebei, China","Payment Terms":"T\/T, Western Union, MoneyGram","Supply Ability":"10000pcs\/month","Packaging Details":"Standard package","Name":"Electrical Transformer Silica Gel Air Breathers","Transformer Type":"Power Transformer","Country of Origin":"China","Flange Type":"Round Flange \/ Square Flange","Feature":"To Absorb Moisture","Breather Type":"Silica Gel","Packaging Type":"Carton Box \/ Standard","Shape":"Cylindrical"}}