There are multiple versions, for the FDM versions there are STLs with and without built-in supports:

• Stock model (for reference or SLA printing)
• FDM printable version, for stock 7.5 mm bulb assembly
• FDM printable version, for 5.8-6.2 mm bulb

Print FDM versions with translucent red PETG, 0.4 mm lines, 0.2 mm layer height. A bit hotter and slower than your typical PETG profile is recommended to get the best possibly layer adhesion and clarity.