Most ICERs seen in use on the show are of a handgun variant, and are wielded by many team members. These are a large improvement over the previous "Night-Night Pistol", as they are much sleeker and more compact, and are said to have triple the effective stopping power against threats.
After the success that the prototype Night-Night Gun showed, Fitz and Simmons upgraded their tranquilizers to become ICERs. Their first test run with the new weapons was in an operation to apprehend Lorelei in the Nevada desert, incapacitating the enthralled victims of the Asgardian.
After the ICER was used in the field, S.H.I.E.L.D. went on to develop different versions of the ICER, such as pistols, shotguns, sniper rifles, sub-machine guns and assault rifles.
In "Who You Really Are", Simmons mentioned that she was working to upgrade the ICER's to have a more concentrated dose of dendrotoxin to increase their stopping power. Fitz told Simmons that could be dangerous, but she argued it was necessary given these new elevated threats they can't risk the ICERs not being effective.
ICER's are useful weapons against ordinary opponents, but have shown to be ineffective against several super powered enemies, including:
- Centipede super-solders
- Calvin Zabo after he's taken his serum
- Hive, and any of his inhuman victims
- Agents of S.H.I.E.L.D.: Season One Declassified