310-00 Envelopes, Plain or Printed

• 06 Envelopes, Clasp, String, Etc.
• 24 Envelopes, Plain Special
• 30 Envelopes, Plain, Stock Sizes
• 36 Envelopes, Plain, Stock Sizes (25,000 and Over)
• 42 Envelopes, Printed Special
• 48 Envelopes, Printed Stock Sizes
• 54 Envelopes, Printed, Stock Sizes (25,000 and Over)
• 65 Envelopes, Seed, Metal or Plastic Closure
• 78 Envelopes, X-ray Film Filing
• 99 Commodities Not Otherwise Classified