Teflon® TFE. Protects against overheating. Minimises bumping during reflux. Accelerates the distillation process. Not harmful when boiled in acids, hydrocarbons, ketones, esters, alcohol or alkaline solutions in any concentration. Unlimited working life. Easy to clean. Does not scratch the glass. Leaves no powdery residues. Teflon® TFE. Protects against overheating. Minimises bumping during reflux. Accelerates the distillation process. Not harmful when boiled in acids, hydrocarbons, ketones, esters, alcohol or alkaline solutions in any concentration. Unlimited working life. Easy to clean. Does not scratch the glass. Leaves no powdery residues.