Ah, those are my
Lamb's World 117th 
As a couple of posters have noted above, it's a fairly simply kitbash of Elysian drop troopers and the Forge World Cadian respirator heads. Note that these heads are considerably smaller than those from the plastic Cadian infantry box; the smaller Elysian bodies look a bit 'bobble-headed' with most (but not all) of the plastics.
As standard, my troops used Elysian torsos with the additional rebreather removed and the cables trimmed back; but I also incorporated some additional bits from other kits - the short-lived updated Necromunda Van Saars, plus the command kits for both Catachans and Cadians (both a bit smaller than their respective infantry kits). Some of them use other bits from the Forgeworld Cadian sets; and plastic Cadian torsos; for these I simply shaved off the additional pectoral plates to reduce the bulk.
'Standard' Lamb's World conversions – all Elysian, except for the heads. Torsos are simply cleaned-up Elysian torsos:
Not a great shot, but the infantryman on the left here uses the propped-up lasgun arm from the Forge World Cadian veteran set.
More bits from the Forge World Cadian veteran set (shotgun), plus a head from the Catachan Command squad:
I think this plasma gun's from the Forge World Renegades:
These guys from my Command
HQ are examples of the shaved-down Cadian armoured torso; here used alongside Space Marine Scout legs and arms from the Catachan Command Squad and
FW sets:
...and more of the same. No real excuse for these; just wanted to post them!
Hope that's helpful, and good luck – would love to see your version
