I see that the IIC is 51, but what is the STC rating for your 5mm?

The acoustical ratings for AcoustiCORK RCLT 5mm Sheet are as follows. Tested for STC & IIC Ratings Per ASTM E 90, E 492 & E2179 51IIC/ 51STC - 6” Slab - 5mm / Hardwood -22 ?IIC 50 IIC/ 54 STC 6” Slab-10mm / Ceramic Tile -22 ?IIC 51 IIC / 55 STC 8” Slab -5mm / Ceramic Tile