The original universal size replacement percolator tops. This set includes a clear, heat-resistant glass perk top plus a patented locking ring in non-corroding aluminum, which will fit most electric and non-electric percolators with cover openings from 13/16 inch to 1-1/2 inch. The Fitz-All percolator top fits tight--it won't fall out! A perfect replacement for older perks where the original glass knob won't fit because the hole is worn or enlarged. Get the old, classic coffee pot back in service!