As I have been thinking of acquiring some 4 pin PL-T triple tube CFL lamps, I have noticed that Osram Sylvania made 2 different types of “Dulux T/E” CFL lamps for the North American market. In one case, you have these lamps marked “Dulux T/E IN” on the etch to indicate that they use an amalgam reservoir while the other “Dulux T/E” CFL lamps have no “IN” on the etch. What are the differences between these two types of CFL lamps and are there any advantages for using an amalgam reservoir in PL-T triple tube CFL lamps?

Here is a normal Osram Sylvania Dulux T/E CFL lamp:

https://www.ebay.com/itm/182896395562

Here is one with “IN” on the etch:

https://www.ebay.com/itm/122525501374

The “IN” lamps are for hot running fixtures which means that the lamp has rather confined space in the reflector thus running hot but still more efficient compared to a normal T or T/E lamp.