These rotors in 160mm diameter weigh 85g. They're 2.0mm thick and have a minimum wear thickness of 1.7mm. In Australia, these rotors are sold by JetBlack and normally bear that name.
What are they like?
They feel slightly less powerful than the Hygia SLP lightweight rotors and when used on the front produce a sort of pulsing/ABS type effect. This is probably as a result of the braking surface having so many gaps. Really hard braking on the front on tarmac (at the limit of front tyre adhesion) will have the front wheel and fork "pulsing" as the amount of brake grip changes as various parts of the rotor pattern goes through the pads. This is not really noticeable off-road as on any dirt surface its all but impossible to get the amount of front tyre grip to get these to pulsate.
"Fuller" style (but much heavier rotors) like these Shimano rotors don't give the pulsing effect. The Hygia SLP lightweight rotors also don't suffer from this even though they are lighter still (80g each) and thinner (1.8mm thick).
These rotors are rebadged and sold by many third parties. In Australia, they are branded Jet Black. In the US, Origin8 sell them as Torq-Lite Rotors for the low, low price of $7.40 a piece.