The ultimate LED refit light; Sigma is a full featured LED down light. hole cut-out size is similar to many of the legacy halogen down lights that it is designed to replace. Sigma is supplied with springs for interior mounting (e.g. headliner-wrapped or paneled ceilings). For secure mounting in to hard ceilings or exterior locations, simply remove the springs and mount with #4 s.steel flathead screws. A 10-40VAC/DC universal input allows Sigma to be used with 12V, 24V, or 32V systems and for voltage supplied by magnetic AC transformer as well.