S = 36-pack, M = 120-pack.Includes 36 business envelopes in the colors coral, pink orange, light orange, light green, mint, lilac, ideal for sending correspondences of all sorts.Envelopes come in 6 pastel colors that are easily noticeable and are for you to mix and match with your inserts.Envelopes are made of 110 Gsm thick paper with a water-soluble gum applied across the square flaps. Simply moisten to activate and close for a permanent seal. Ideal for sending marketing materials, tri-fold brochures, standard letter-sized documents folded in thirds, personal checks, small stationeries, and more.Each envelope measures 4.125 x 9.5 inches. Weight: 0.55 pounds.