Heteromask Spray Grub Killing Beneficial Nematodes (Heterorhabditis bacteriophora) Sprayer Pack 50 Million Heteromask contains beneficial nematodes which are an all-natural alternative to chemical insect pest controls. Easy to use: just add to watering can, pump sprayer, hose end sprayer, or Nema-Jet Sprayer. Kill grubs without exposing your pets or family to chemicals. Treats up to2630 square feet and is safe for people, pets, and plants! BioLogic produces and ships Scanmask directly. Shipped in an insulated box with ice to ensure quality.