How to identify a blow-out pipette?
Good to see classical analytical chemistry queries. These graduated pipettes or Mohr pipettes they are called, confuse even the relatively advanced users. First you have to check where the graduations end. If the pipette was meant to deliver 10 mL or 50 mL you should not see 10 or 50 mL mark near the tip of the pipette. That is one hint. Add a picture of the tip as well. Secondly, a double ring indicates that all liquid has to be expelled.
Notice that when you are doing very high precision work, one has to know the full drainage time as well after the liquid has been delivered. For example, after delivering 10 mL you need to wait for 5 s before blowing out the last drop. Very high quality glassware use to mention this time on the glassware.
In your blurred picture one can se Ex 5s, which means wait for 5 s before blowing out the last drop.
Volumetric pipettes should never ever be blown out, but they also have a drainage time, you have to wait for a certain time before dislodging the last drop purely from surface tension effects.