Wafer Tab Seal Labels, these are round adhesive dots for sealing mailers weighing over 1 ounce - 1 1/2" Circle 4,000 per roll, carrier width 1 1/8" 

These non-perforated clear translucent frosted adhesive paper dots tear apart when needed and can be used on postal mailing pieces, they meet USPS regulations as of Jan 2013.  

If the mailing piece is over one ounce then a 1 1/2" or a 2" non-perforated wafer should be used.