These are small honeycomb breadboards with a flange on the bottom plate for easy mounting. Being a honeycomb assembly, they are much lighter than comparable solid aluminum mounts and are ideal for elevating heavy centered loads The top surface has an array of 1/4-20 tapped holes (or M6) and the bottom flange has 1/4" slots. Available in 0.8", 1.3" or 2.3" thick. Custom sizes avaialable.