The box on your left is an early Philips sleeve from the old sealed type box. The two on your right are relatively new from right after they bought Sylvania including the entire ECG line. Having previously bought out Amperex that made PHILIPS a dominant force in vacuum tubes. The only problem was that these were the waning days of tubes.
The first box of those on your right is identical to the last box that was used with the Sylvania name. Even though now owned by Philips the tube in the box may just as well have been branded Sylvania. Philips did not run out and rebrand every tube after
the buyout. All three of these brand names associated with Philips were top-notch first rate tubes. Philips produced quality tubes right to the end of their tube era.
PhilipsECG went with the Sylvania coding system of both 2 and 3 letter codes on a tube. See my comments on the Sylvania and EIA/RETMA code pages.
ECG was Sylvania's name for their large semi-conductor replacement series. They expanded it to cover tubes and other replacement parts. Now under Philips, ECG covers Test Equipment and a whole bunch more. ECG means Electronic Components Group.
Update: In the winter of 2001, NTE bought the entire ECG line. This did not include tubes since ECG ceased tube production/purchasing prior to this.
Here's an additional semi-conductor side note. Many of you may remember when NTE (NewTone Electronics) first began seriously competing with Sylvania's ECG they used the same numbering system as ECG with the letters "TCG" as their prefix. TCG meant Technicians Components Group or Technical Components Group depending on who you ask. Sylvania sued them for it being too close to ECG. Sylvania won and NewTone Electronics switched to NTE for a prefix which is still in use. Now NTE owns ECG. What goes around comes around!