The Swarovski Optik BTX Modular Binocular Eyepiece can be used with all 4 Swarovski Optik Modular Eyepieces. With the 65mm and 85mm objective lenses, your scope will have a fixed power of 30x. With the 95mm and 115mm objective lenses, your scope will have a fixed power of 35X. 
This listing is for the BTX Eyepiece only. The pictured objective lens is not included, but they are listed here at Honey Creek Bill & Beak.
Honey Creek Bill & Beak is an Authorized Swarovski Optik Dealer located in central PA.
Thanks for looking.

PRODUCT DESCRIPTION

The BTX combines the visual power of both eyes with a revolutionary viewing experience. Crucial subtleties can be seen with the crystal clear optics, with every detail now fully on show. A forehead rest and angled view guarantee comfortable viewing for hours on end. The benefits of binoculars and spotting scopes are combined in the BTX eyepiece module. It presents vivid, true-to-life images and offers the comfort required for long-term observation. The BTX eyepiece module is compatible with all objective lenses in the SWAROVSKI OPTIK ATX/STX range.

SIZE & WEIGHT
6.9 inLength in mm.
50 ozWeight
ENVIRONMENT & CONDITIONS
-13 to +131 °FFunctional temperature
-22 to +158 °FStorage temperature
13 ft (4m) water depth (inert gas filling)Submersion tightness