Roberts Black Jack Is Engineered As A Superior Grade 2-In-1 Underlayment For Laminate And Engineered Wood Flooring It Is Ideal For Use With Many Types Of Subflooring This Product Is Designed For On Or Above Grade Installations The 2.5 Mm Thick Foam Layer Provides Optimal Cushioning, Sound Absorption And Even Levels Minor Subfloor Imperfections The Closed Cell Foam Design Provides Excellent Moisture, Mold And Mildew Resistance Includes A 4 In Overlap And Adhesive Strip To Seal Out Moisture And Join Multiple Rolls 100 Sq Ft Coverage With Rolls Measuring 28 Ft X 43 In X 2.5 Mm The Black Jack Has A Sound Transmission Lost Test (Stc) Rating Of 65 And Impact Sound Transmission Test (Iic) Rating Of 68 Also Has A Delta Rating Of 20.