Maximizing education investment & collaborative learning with ultra-short throw projection, the Ben Q LH890UST utilizes the unparalleled qualities of a laser light source to achieve optimized performance, long-lasting reliability, and energy efficiency for the leading schools. Superior dustproofing design to prolong projector lifespan Ben Q LH890UST is designed with Dust Guard technology including sealed laser modules to protect the laser bank. This lock-&-key design hermetically seals the laser engine from dust to prolong projector lifespan. Brilliant display of lecture content LH890UST's powerful Blue Core laser projection utilizes a dual color wheel system to produce outstanding color performance by increasing color ratios & purity of RGBY colors, greatly enhancing color saturation & brilliancy at the same lumen output of lamp-based projectors to deliver superior viewing experiences. Laser-enabled ultra-high contrast LH890UST laser projectors create strikingly clear images with stratospherically high native contrast ratio of 100, 000:1 for true deep blacks, vividly rich colors, and fine subtle details. LH890UST also features spontaneous response, requiring no wait to turn on or resume from blanking in true black for flexible performance capability. Long-lasting high brightness LH890UST produces 4, 000 ANSI lumens & superior brightness efficiency, at the same level as IFPs for clear, sharp images & text even in large, bright classrooms. High brightness allows lights to be kept on during lessons, and sealed laser banks prevent dust entry to minimize brightness decay for long-lasting high brightness.