NEC LT240 User Manual page 122

MAINTENANCE
Lens Protector
The lens barrel has threads on the outside for mounting a commercially
available lens protector ( 62mm for LT260/LT220 and 72mm for LT240)
to protect the lens from dirt, dust, scratches and damage. Note that both a
lens protector and the supplied lens cap cannot be used at the same time.
CAUTION: Use only transparent lens protectors designed for lens protec-
tion. Use of filters for light reduction and special effects, such as ND (Neu-
tral Density) filters and color filters, can absorb heat, resulting in damage
to the filter and the projector.
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