Looks like Aluminum--slick setup--and light!
I saw several aluminum trailers a little like this one in southern Indiana a few years back--will see if I can find the photos and manufaturer--
featherlight makes some aluminum trailers-but they are pretty pricey!
1989 BlueChevy 1500 Extended cab with FULL bed
1978 7ft Sears cargo trailer with added wood inserts to hold both my weedeaters
3 1976-83 vintage lawnboy lawnmowers with full self propel features as well as mulch kits
2 Sears electric weedeaters
1 green machine electric leaf blower
1 sears articulating hedge trimmer-electric
2 50ft power cords
3 Leaf rakes
1 pocket knife
cooler for beer
lawn chair to enjoy a beer while I wait for the cash to be handed to me