Spectral transmittance of Plexiglas® XT Clear 20070. The material, an extruded acrylic (polymethyl methacrylate) was used for the heat exposure chambers. For visible and near infrared light (1200 nm > λ > 380 nm) it is highly transparent (ψ = 95%). Even the physiological relevant spectral ranges of UV-A (380 nm > λ > 315 nm) and UV-B (315 nm > λ > 280 nm) are transmitted by 80% and 50%, respectively. λ wavelength, ψ spectral transmission. Source: adapted from Röhm GmbH, Darmstadt, Germany.