BSP female x BSP male coupling. McAlpine BSP Coupling 2" Long 1 1/4" S12A-2 in White. A leading supplier of plumbing fittings, Mc Alpine comes with a variety of high-quality and competitive products to suit all plumbing solutions. This coupling design offers good airflow characteristics that make it suitable for domestic repair, maintenance and improvement work. Enhance your plumbing installations with the McAlpine BSP female to BSP male coupling. Crafted from durable polypropylene, this compact 2 Inch coupling is designed for reliable performance in various plumbing applications.