Hamilco White Cardstock Thick Paper - 5 1/2 x 8 1/2" Blank Index Flash Note & Post Cards with Envelopes - Greeting Invitations – Heavy weight 80 lb Card Stock for Printer - 100 Pack (Bright)

This acid-free, 80 lb cover cardstock is 5 ½” x 8 ½” and comes with matching 5 ¾” x 8 ¾” square flap envelopes. It is compatible with laser, inkjet, and copier printers and is packaged in a sturdy box.

• The description claims the cardstock is the ultimate choice for various uses.