Gamma Seal Lids are a two piece sealing system that allows you to transform a standard bucket or pail into an easy to use air tight container. Gamma Lids fit most 2 gallon and 3.5 to 7 gallon plastic pails and buckets (10" or 12" diameter). Snap the adapter ring to any 12" diameter bucket, then spin on the heavy duty gasketed lid. Re-seals Your Bucket. Easy Opening Lid. Spin off to open, Spin on to close. Food Grade Plastic, BPA Free.