Standard Substance Weights-Wove
16 lb. Used for overseas air mail envelopes.
20 lb. Used for commercial envelopes where strength & opacity is not a factor.
24 lb. Workhorse of envelope papers-used for most open-side official and commercial envelopes.
28 lb. Used for most open-end and catalog envelopes and larger size commercial envelopes.
32 lb. Used for heavy duty envelopes and clasp envelopes.
40 lb. Used for large envelopes, heavy duty envelopes or envelopes used for frequent re-use.
