The exact retail parcel size for IsoAcoustics GAIA B&W mounting plates is typically around 6.6 x 6.6 x 1.27 cm (or 2.6" x 2.6" x 0.5") and weighs about 218 grams (or 0.5 lbs) for a 4-pack. 

This small size reflects only the dimensions of the plates themselves, as they are often sold as an accessory or adapter. 

The round plates measure 66mm (2.6") in width/diameter and 12mm (0.5") in height.

The D3/D4 specific plates measure 65mm (2.5″) x 48mm (1.9″) x 12mm (0.5″). 

If you are shipping these as part of a larger order (e.g., with the GAIA isolators themselves), the overall parcel size will be larger, typically around the size of a shoebox or slightly larger, and weigh more, depending on the specific GAIA model they are paired with (GAIA I, II, or III).