Swarovski's new revolutionary BTX binocular spotting scope eyepiece brings unheard-of comfort to long range optical viewing. Compatible with all ATX/STX objective lenses, the BTX eyepiece module changes the way you'll think about spotting scopes. BTX FeaturesPerfect fit to SOC Objective modules - 65mm, 85mm, and 95mm objective modules are all supportedObserver now can use both eyes all the time when scoping, enhancing user comfort and ergonomics and providing amazing image qualityDoes not have a zoom eyepiece, but is compatible with optional 1.7x Magnification Extender (49230)Eyepieces are adjustable for interpupillary distanceRight eyepiece adjusts for diopterForehead rest provides enhanced user comfort and stability, and is adjustable for optimum viewing distance from ocular lensesIntegrated peep sight for quickly finding remote targetsSWAROVISION Field Flattener and High Definition Lenses give perfect clarity, eliminate distortion, offer increased eye relief, and bring out ulimate color contrastsSWAROTOP, SWARODUR, and SWAROCLEAN lens coatingsFunctional Temperature: -13° to 131° F Swarovski Optik Swarovski BTX Eyepiece Module 49903