Pan-Gel safe, easy to use. Starts working immediately, unclogs drain lines, prevents corrosion, eliminates stale water odor, ready to use (no mixing), and stops overflowing drain pans. Easy to use. Safe, pre-measured tablets formulated with the compound AT-8 has “Inviso-guard TM” that keeps your A/C drain pan clean of slime, scum and other accumulations keeping the drain free flowing. Continuous use prevents annoying and costly maintenance problems due to clogging drain lines and overflow pans. Continuous use also eliminates the source of swampy, foul, musty odors so prevalent in A/C units. Does not release any chlorine or other noxious or toxic fumes.