50 PIECES IN 1 SET - The envelopes are exactly measured 6 1/2 x 4 3/4 inches, perfect for 4x6 cards and suitable for weddings, birthdays, baby showers, graduations,holiday, party invitation,letters, hand made cards and more. HIGH SECURITY - The thickness of our envelope is 250GSM, which is thicker than normal envelopes, your privacy will be well protected.But because of the thickness,it won't go through printer. EASY SELF SEAL,SIMPLE TO USE - No need to seal with an glue or tape, just peel and press.Also the adhesive tape is strong, please feel safe to use it. V-FLAP ENVELOPE DESIGN - They have an elegance look with gold foil borders on the front of the envelope, come with natural touching feeling and pretty colors.