Your pic just got me interested, since I'd never seen marked bottles. Didn't take me long to find them since they popped up in my very first search for them. 
I do like that they're marked, but I'm not really crazy about the taller neck on them, because of the tamper evident cap with the ring on the bottom. But it's not a deal breaker for me.
I assume, since there aren't enough marks between the 25 and the number 50 to go by 5mLs...that 50mL is up to the line that goes all the way around the bottle.
Also, I noticed this seller only carries the marked ones in 50mL. Found another seller who also sells them in the 30mL, but that seller's bottles are slightly more expensive + $2.48 S/H by ePacket.
I can't decide now. Do I want them, or just keep using the ones I have, that I put a 1" fine Sharpie line at the 30mL and 50mL marks for my 60VG/40PG mark? These would definitely be more useful for various PG/VG ratios though, since all the markings are on them, no matter what ratio someone is making. Might help a couple people locally that I'm teaching my method to also.
EDIT: Question for you about the tips - Are they the one-drop-at-a-time dispensing tips? But you can poke a large gauge needle through them to make them streaming tips? Or are they already the streaming ones?
I do like that they're marked, but I'm not really crazy about the taller neck on them, because of the tamper evident cap with the ring on the bottom. But it's not a deal breaker for me.
I assume, since there aren't enough marks between the 25 and the number 50 to go by 5mLs...that 50mL is up to the line that goes all the way around the bottle.
Also, I noticed this seller only carries the marked ones in 50mL. Found another seller who also sells them in the 30mL, but that seller's bottles are slightly more expensive + $2.48 S/H by ePacket.
I can't decide now. Do I want them, or just keep using the ones I have, that I put a 1" fine Sharpie line at the 30mL and 50mL marks for my 60VG/40PG mark? These would definitely be more useful for various PG/VG ratios though, since all the markings are on them, no matter what ratio someone is making. Might help a couple people locally that I'm teaching my method to also.
EDIT: Question for you about the tips - Are they the one-drop-at-a-time dispensing tips? But you can poke a large gauge needle through them to make them streaming tips? Or are they already the streaming ones?
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