The in-line F3MM lamp holder is packaged with optical-grade epoxy resin. This type of device has a long service life and can effectively reduce maintenance costs. It has the characteristics of high energy efficiency, fast start-up, and low-voltage DC drive. The packaging is moisture-proof and anti-static packaging, which complies with ROHS Requirements, it can be applied in the fields of Internet of Things, medical treatment, converters, status indicators and electronic test instruments.