Simple, straightforward utility replacement SES lampholder.  Ease of replacing as it is supplied in 3 parts.  The base has  an M10 thread entry.  the insert has 2 terminals (we should note at this point this lampholder cannot be earthed it is completely double insulated), then  the smooth skirt screws down onto the end cap and locks into place.  This fitting is often found on lights bought from the continent.  Many multi-arm fittings would use these. Screen reader support enabled.

If in doubt consult an electrician.