DLK Model 1-1/2
1st gen - foam grilles, cast DLK emblem attached to bottom right corner of grill, woofers evenly spaced vertically, phenolic ring cone tweeter, round plates on back of cabinet
2nd gen - fabric grilles, "DLK/1 1/2" on horizontal strip across grille towards the top, woofers offset vertically towards the bottom of the cabinet, phenolic ring cone tweeter with guard over it, square plates on back of cabinet
3rd gen - "NEW DLK 1-1/2" - fabric grilles, small DLK logo on bottom right corner of grille, woofers evenly spaced vertically, soft dome tweeter, round or square plates on back of cabinet
"4th" gen - DOMUS model 2 - had a horn tweeter
There was also a Soundmates model (made by DLK) that was essentially a variant of the 1-1/2 design.
I've owned the 1st gen and 3rd gen as well as DOMUS 2 in the past. I preferred the 1st gen. The 3rd gen had a different style sound to them. I've never owned 2nd gen but they should sound pretty much the same as 1st gen.