Square with double curvatureMineral crystals CRT-Bestfit, domed both sides. Products nameVersionmaterialABthicknessitem No.CRTdomedsapphire17.0014.90-CRT170149CRTdomedsapphire20.5017.50-CRT205175CRTdomedsapphire22.0019.00-CRT220190CRTdomedsapphire22.5019.00-CRT225190