Background
GaoJie soldering tools are manufactured by Guangzhou Huanghua Electronic Tools Co., Ltd. Guangzhou Huanghua Electronic Tools Co., Ltd. was founded in 1984 and is a professional manufacturer of soldering tools (and glue guns) in China. The headquarters is located in the Creative Avenue Park of Huanghuagang Science and Technology Park in the National High-tech Zone of Guangzhou. You can learn more here.
Identification
GaoJie branded products typically have the "GJ®" logo or, particularly on older products, the words "GaoJie" will be present in all caps, as can be seen on this image. Above the GJ® logo are the Chinese characters, 黄花高洁, which translate to Huanghua Gaojie, perhaps a representation of the "fusing" of the two brands, Huanghua (shorthand for the parent company) and GaoJie.
Some popular GaoJie products are the 970S soldering iron and the s-993a desoldering gun.