This listing is for a Pack of 1 Important Sizing Note - Most plumbing products are measured using BSP thread dimensions which measure 1/4 inch larger than that stated, therefore this 2 1/4 Inch BSP thread actually measures 2 1/2 inches in diameter. If your thread measures 2 1/4 Inch in diameter then you require the 2 Inches version of this product This immersion heater plug is for capping off an immersion heater 2 1/4 inch BSP flange Comes complete with sealing washer Made of brass