• Constructed From High-Density EPS (Expanded Polystyrene) Foam • Includes 2 PROVA LINEAR PAN EXTENSION® • Can Be Used To Extend The Size Of A Linear Shower Base By Adding Them To Existing Linear Pan Pieces • Premium Polymer-Modified Thinset Mortar Required For Installation (Premixed Mortar Or Mastic Are Not To Be Used) • Mfg #TT8902EXT02