6x9 sil poly tarp weighs 8.5 oz. The 6x9 is made from generation 2 sil-poly.The 2nd generation of our Silicone double coated 1.1 oz polyester ripstop (silpoly). Unlike most ripstop fabrics that use the same yarn throughout, our 2nd Gen silpoly uses a thicker yarn for the ripstop grid coupled with a thin/light base fabric. The result is a highly durable, abrasion resistant fabric with very little stretch/sag when wet. All seams are sewn with gutterman upholstery thread. Corners and guy outs are reinforced. Minimun number of stakes needed is 4, max is 6-8. Rope for guyouts sold separatly. PLEASE NOTE- THIS PRODUCT REQUIRES SEAM SEALING (WE RECOMMEND GEAR AID SEAM GRIP + SIL SEAM SEALER, WHICH IS AVAILABLE AT MOST BIG BOX SPORTING GOODS STORE AND ON AMAZON). FOR TARP STAKES WE RECOMMEND EITHER THE EASTON NANO 6' OR THE MSR GROUND HOGS.