Pen Brushes - Sakai from Saizen

Just bought two different Japanese penbrushes. It's called Sakai. These pens are cool because they're waterproof, meaning it can't be washed by water.

Above are the pens. The one on the left is the BLACK and on the right is the PALE BLACK or grey. Both are waterproof so I don't have to worry if my drawings will turn brown 10 years from now.

Below are the nibs of the brushes. The first two are the nibs of the BLACK pen on both ends. So it's a two-in-one pen. The small nib is like a crow quill or a tiny brush which is cool and is what I'm looking for. The third is the PALE BLACK or grey.

There are some other brushes in Saizen Japanese (Robinsons Galleria, Ortigas Ctr.) store that I wish I could try. Oh, and each pen is P85.00. Pretty expensive but it's worth the try.