Standard: 4"×3" 3.5"×3.5" 4"×3.5" 4"×4" 5"×3" 5"×4.5" 4.5"×4.5" 5"×4" Content: Core Diameter:Ø10-14mm Board Thickness: H2.0-3.5mm Material: Steel, Stainless Steel ,Iron, Aluminum , Brass,Copper. Can be manufactured to a customer's drawing or design.