The kit is resin and they hope to have it available soon.
From the post:
Walking into Carnage Destruction and Mayhem!
Hooray! Our new walker vehicle has been cast and has arrived at back Terragnosis in all its resin, multiple weapon, multi-pose glory! This big ole beast has a satisfying array of weapon options and leg/arm configurations, not to mention armour plates, pincers and big tooth saws. Here are the pics of the first ones we have assembled.