Threaded Plastic Plugs, 130608 Red Poly Plug, 100 Bag | StockCap
Caplugs 99390176 Plastic Threaded Plug for Pipe Fittings. P-48, PE-HD, to Plug Thread Size 1/2 NPT", Red (Pack of 50): Amazon.com: Industrial & Scientific
Brackit 100 Pack Masonry Rawl Plugs - 6x30mm (1/4"x1-3/16") - Heavy Duty Plastic Wall Plug Fixings for Brick, Concrete, Stone – Ideal for Building or Hardware - - Amazon.com
Caplugs Plastic Hex Socket Threaded Plug. TH-3, HDPE, to Plug Thread Size 1/4-18", Black (Pack of 700): Amazon.com: Industrial & Scientific