US Patent 7854337 Breakaway closure member with offset nipple

A breakaway closure member for removably covering an opening in a plumbing device, such as a laundry box, pressure test cap, floor drain, shower drain, closet flange, or the like includes a circular disc with a peripheral rim and a hollow nipple extending outwardly from the circular disc. The peripheral rim is connected to the plumbing device by a thin web or area of reduced thickness. The nipple is radially outwardly offset from the center of the disc so as to be generally adjacent or tangent to the peripheral rim. If the nipple is radially compressed, such as by squeezing with a pair of pliers, the peripheral rim is pulled radially inward in an area proximate the nipple, thereby creating a crack in the area of reduced thickness.