Actual Sizes: 7-1/2" x 7-1/2" x 3-1/8" Inch Perfect Decor: Build walls or incorporate into outdoor designs with ease. Decorate any room of your home. Glass Block is very versatile. The Optical pattern glass block has flowing lines that gives it the impression of flowing sand on the dunes. Multi Uses: Rated for commercial use, ideal for high-traffic areas like offices or public spaces. Glass Blocks make an excellent source of security to keep intruders out. 45 Minute Fire Rating. A white bond coating is applied to each block for mortar adhesion. There are no holes for crafting in this block. Visible Light Transmission: 80% Sound Transmission S.T.C. (dB): 37 Thermal Resistance R-Value: 1.89 Seves 1919/8 Optical Pattern Glass Block – Flowing Wave Design for Unique Light & Style Break away from the ordinary with the Seves 1919/8 Optical Glass Block. Designed for those who prefer soft curves over straight lines, the Optical pattern features fluid, wave-like textures that resemble wind-swept sand dunes. This artistic glass block brings movement and dimension to any space while allowing natural light to filter through in a soft, elegant way. Ideal for residential or commercial projects, the Optical block adds personality and sophistication to walls, windows, and partitions.