The “geysering” effect has long been a problem for the termite specialist. Because liquids follow the path of least resistance, the next drilled hole may geyser pesticide. By using Super Plugs, however, the pesticide is forced to remain under the concrete — allowing a thorough treatment without the danger of liquid pesticides spilling in the structure or exposing the technician. The flush-finished top of the plug allows the option of counter-sinking it for concrete patching. Super Plugs are made of tough, chemical-resistant polyethylene for long life, while retaining their tight seal to prevent vapor escape.
from Pest Management Professional https://www.mypmp.net/2018/12/17/executive-pest-control-products-super-plugs/