This set of Artist Cards and Envelopes from Moab includes 100 heavy-type 4.5 x 5.8" cards and 100 matching envelopes for printing and sending greeting cards, invitations, promotional cards, and more. The cards are actually about twice as large. The 305 gsm sheets are printable on both sides and inkjet-coated to support high-quality, high resolution printing of photographic and fine art images. They're prescored at the middle so you can fold them in half to make 4.5 x 5.8" cards. The envelopes are roughly the same size as the folded cards, and both the cards and envelopes are made of 100% cotton. The envelopes are not inkjet-coated nor intended for high-quality printing, but you can print addresses on them.
The cards are compatible with most photorealistic inkjet printers. Moab offers templates for Photoshop and Lightroom on Mac and Windows to help design your cards.