The Paper Arts site talks about everything related to paper including stationery, scrapbooking, and DIY paper projects.

Colorful mix-n-match stationery is always a fun thing, and here’s a good example. This is a collection of fun and fresh mix of so-called “sushi-paper” by Amy Ennis (published by Chronicle Books) that includes both the stationery paper and envelopes.

You can pretty much mix the envelopes and paper up any way you want. This might be a great gift for that rare breed of friend who still enjoys writing an honest to goodness physical letter once in awhile.

I believe there are 16 pieces of Sushi-nery paper included inside (someone had said there are also stickers included) and measure 7.7 x 4.3 x 0.3 inches according to Amazon.