The CS series is I think their oldest line and uses a metal case. I've charged at a few of them that based on the fading of the finish appear to have been mounted outdoors for quite some time. They scream "heavy duty."
The HCS series I think uses a plastic case, like the LCS series but larger. When I got my LCS-25 back in 2013 I don't think the HCS was around yet, so it's probably the newest line. LCS can also be "mounted anywhere" per CC but while a good unit it's probably not as rugged as the CS or HCS.
Blue Ocean 2012 Leaf SV, lost that 1st bar on 11/21/2015 at 26,435 miles.
Lease returned on 12/23/2015. Final LeafStat figures: 225 Gids, 17.44 kWH, SOC 91.89%, SOH 82.36%, 69.49% HX, 54.57 Ahr, battery temp 61.8 F
Now driving a 2015 VW eGolf SEL