SUPER FAST SHIPPER HIBISCUS EXPRESS .... [[ 6" x 4" POSTCARD ]].. . . .. from HibiscusExpress .... // .. .. Our postcards are printed on 16 pt (360 gsm) premium sturdy quality cardstock. ..... //// ..... This is the maximum thickness allowed by USPS for a postcard to be mailed without an envelope.... Made in USA. .. from HibiscusExpress