GK Bullet not showing in K2 article

Hello,
I used <ul class="gkBullet4"> but ik K2 articles this bullet style is not showing. In a normal Joomla article this works fine. Can you tell me what is wrong?

Link to website: http://www.bandoutoftime.nl/repertoire

Thanks in advance!

Hi,
but under firefox

Hi,
I know, but these aren't the correct bullets. That's my point, see attachment

OK, now when I checked I've found typography issue, you're right. Opsss.
Please use:

ul.gkBullet3 li:before {
content: "\f006" !important;
}

Thanks! That did the job, problem solved