🔍 Flask Your Way to Success! Heavy-duty rim ensures longevity and reliability in every use. Rubber stoppers provide a tight seal, preventing spills and contamination. Narrow mouth design allows for controlled pouring and mixing. A must-have for any professional or aspiring chemist. Perfect for all your experimental needs with 5 distinct sizes. Rubber Stoppers Included 5 Flask Sizes Narrow Mouth Design The Pyrex #4980-PACK(RS) Narrow Mouth Erlenmeyer Flask Set includes five essential flask sizes (50, 125, 250, 500, and 1000ml) with durable rubber stoppers, designed for precision and reliability in laboratory settings.