. 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 & energy efficiency for the leading schools Key Product Info. Superior dustproofing design to prolong projector lifespan Brilliant display of lecture content Laser-enabled ultra-high contrast Long-lasting high brightness Product Features 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 100000 1 for true deep blacks vividly rich colors & 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 4000 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 & sealed laser banks prevent dust entry to minimize brightness decay for long-lasting high brightness.