Plastic, it's a cheap recast and doesn't have the name of the original one but I think it's the same you're talking about (maybe Halcyon), as the seller also has the long nailed and chestbusters. There's also a queen chestbuster which I was tempted to buy, but thought it would be too complicated for a first kit, so went it something with just a few big pieces.Is that the rubber kit or a plastic one?
Back in 1992 (when Alien 3 came out?) there was a 1:1 face hugger and 1:1 chest busters of both the alien that came out of both human and the dog. Each was about $200 and very detailed. I've not seen them since.