... type: Base: iron and copper, alum for choosing in E27, E26, B22 ,E14 .Color tempreture: 2700K to 6400K Frequency: 50Hz . ... in by holding the glass tube10.International certifications: ISO9001:2000,CE,ROHS;GS,CCC,QC, Energy Star etc. Why Choose Ebeteb Lighting ... 's cooperate to build the longterm business together! energy saving lamp with CE/ROHS approved