310	ENVELOPES, PLAIN OR PRINTED
31006  *	Envelopes: Clasp, String, etc.
31024  *	Envelopes, Plain, Special
31030  *	Envelopes, Plain, Stock Sizes
31060  *	Envelopes, Recycled Paper
31065  *	Envelopes: Seed, Metal or Plastic Closure
31067  *	Envelopes, Shipping and Mailing
31078  *	Envelopes, X-Ray Film Filing