hi, can someone explain me about st111 starters?
i bought some of them and they seems very lazy to start.
i recovered also some unknown name very old metallic case starters and they work very fine 

They do this only with T8 lamps. I noted this in the storage of Carmel hospital.
Osram ST starters aren't recommended, because they have a built in planned obsolescence: Their capacitor designed to die when a fluorescent lamp reaches EOL, resulting in a stuck starter at lamp EOL.

Did not notice anything special with them. Work well for the 36W T8s i installed them in

As for the planned obsolescence : SO RELAMP IN TIME or you'll have to replace a blown ballast whether the starter stucks or not

Ash: Business and public places can't replace the lamp as soon as it starts to flash. Most public areas have a scheduled time for relamping.
The starter should be designed that the EOL will broke a cathode after a day or more, and the starter wouldn't be stuck. This will prevent the damage for the ballast.
This is also the reason why programmed start electronic ballasts have EOL protections and 230/240V instant start/PTC electronic ballasts fuses the electrodes of the lamp at lamp EOL.

For public places which makes a quick replacement of a EOL lamp impossible some special starters are required like the OSRAM DEOS St171, St172 and St173 Starter which has a kind of EOL thermal protection and reset button after relamping! 

Ash: Business and public places can't replace the lamp as soon as it starts to flash. Most public areas have a scheduled time for relamping.
The starter should be designed that the EOL will broke a cathode after a day or more, and the starter wouldn't be stuck. This will prevent the damage for the ballast.
This is also the reason why programmed start electronic ballasts have EOL protections and 230/240V instant start/PTC electronic ballasts fuses the electrodes of the lamp at lamp EOL.

If i'd not be into lighting, sitting in an office and having a flashing lamp above my workspace or in eye sight, i'd bang the head out of maintenance guys untill they remove it NOW as it annoys me

Which makes me think, maybe this capacitor in Osram starter is just to stop flashing as soon as possible so that maintenance won't be bombed with relamping jobs from annoyed cubicle workers ?

In our office are used 3xF18T8 connected as one series pair and one single in a recessed fixture. As long I'm working there (since 1999), I do not remember any single flashing lamp. Each two years are 1/4 of the lamps replaced, what mean after about 20khours, when there are no failures yet.
The replaced lamps may be still working, but their reliability become way worse after that time (so they start to really dying after few khours), so it does not make sense to save 10..15% of the lamp life by having annoyed and unproductive people trying to work underneath...

The contrast is on toilets, where are PL-C's with magnetic ballasts and integrated starters. The building owner wanted to "go green" and ordered the maintenance guy to install the PIR switches. Results are lamps failing after about two months (the maintenance guy write on them the date of installation)...