There is a third connection on the motor

With a fully-sealed motor housing and Integrated electronics

see Fresnel Lenses

D) 72 x 408 x 67mm (including bracket)

the ME-SBC prevents underor over-charging

Vetus PM141 - Porthole type PM141 CE-A1 338x122 Hubbell There is a third connectionHeavy duty portholes! These portholes are suitable for use in the hull side. The 10mm smoke coloured opening pane is set in satin anodized aluminum frame. Black and white powder coated frames are optional. The clamp fixing ensures that no fasteners are visible fromeither inside or outside. The portholes can be fitted in a surface with a minimum thickness of 2mm and a maximum thickness of 18mm. As standard a mosquito screen is supplied. A fixed version