Looks like a PH 4/3 but isn't!
The Penta (below) is a little-known Fog & Morup light designed by Jo Hammerborg and first appearing in the record in 1965. More traditional in form and rounded in shape than most other Hammerborg designs of the period, the light is perhaps unsurprisingly often mistaken for Poul Henningsen's PH 4/3 for Louis Poulsen, pictured in orange here following the lilac Penta.