Vintage 1981 brass Texas oil drilling belt buckle

Nice information stamp on back of this American made brass buckle. Measures 3 1/2” x 2 1/4” More about Hydril: Hydril is a Houston-based company that manufactures pressure control and connection products for oil and gas drilling. Hydril is also a trademarked name for a section of a blowout prevention system (BOP) stack that uses a large rubber "donut" to seal on irregular surfaces. In the 1930s, Hydril was the first company to develop the hydraulically operated BOP and annular BOP.