These building blocks are for the Rcom Bird as well as Curadle brooders 
Building Rack for R-com brooders enables you to stack brooders two units high. 
Please note, both brooders need to be the same size, both large or both medium for the building racks to fit properly 
These building racks can be used with any Rcom Brooders and Curadles. 
Please see pictures which will indicate the brooders and building racks.