The adapter allows you to easily and quickly connect a daytime telescope with an outer diameter of the eyepiece eyepiece ? = 40.3 mm with the night vision cap Bestguarder HD Pard NV-007 (NV-850 Patronus V3 / V4 / V5). The attachment creates a stable connection between the telescope / camera and night vision, without losing zero or reducing accuracy. Mounting screws included.